PH going up over night to 7.8 from 6 in Rain Tower Hydroponics

doctorman(7b / indoor)March 25, 2014

Hey Guys,

my first post here and I hope to resolve my PH problem with you help!

I have an indoor RainTower Hydroponics (something like this )

it is 5"*5" fence post with holes on 4 sides and 3" net pots with hydroton as media. Water gets pumped up 6 feet and rains down every 15 min on-off.

I have 400w induction light on top and reflecting surfaces around.

There are 3 bushes of plants in the system now
1) green sweet basil
2) Purple basil
3) sweet mint

I use tap water, my water is alkaline at 7.8 and is medium hardness, so I struggled with this system for a week fighting the PH with vinegar and one time with lemon juice. I had slime build up and cloudy water that I believe was from the vinegar so I bought GH PH Down Dry and replaced it..

The issues is this..
I adjust my water with PH down to 6 pour it in the system with or without nutrients in hours my PH goes up and by the next day I am up to 7.8 or so.. I keep adding PH down to the system twice a day to keep it under 7. I can not understand what is causing my PH swing so fast.

Some said the plants are taking up so much P that makes your PH go up.. I added more phosphor and ended up bittering up my basil plant..
could it be bacteria? should I run bleach 1 tbsp/gallon in there for couple of hours?
I can not belive 3 little plants could cause my PH swing in hours.. but again I am new to this..
any ideas guys?

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PupillaCharites(FL 9a)

You have done the right things and have a very good system. You are right about the vinegar, since it will result in being eaten by microbes.

You probably just put too much carbon (vinegar) in the solution making it a growth medium for them which resulted in a spike of unwanted scum growth, and also should check you have good aeration to minimize that. The effect of the vinegar in that situation certainly wouldn't last much more than a day.

How long haveyou been using the new pH Down and with what results? What fertilizer mix and rate are you using?

It's not clear whether you are still using the same nutrients that have the vinegar or if you changed them. Don't run bleach with the plants or old nutrients in there, just start with new nutrients, your reservoir is only like what, 5 gallons. Take a peek at the plants roots without damaging them and see if they are all slimy. If they are, then it is probably worth starting over and in that case you can wash the system with dilute bleach, but be sure to rinse it off really well before you start over. If they aren't all slimy you might be ok since the rain tower design is better than a DWC in that respect.

This post was edited by PupillaCharites on Tue, Mar 25, 14 at 12:21

    Bookmark   March 25, 2014 at 12:13PM
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doctorman(7b / indoor)

I should have look at the roots..
many of the roots are slimy and dark .. they look like lost cause but the plants look beautiful..
maybe I wash the roots with H2O2 or bleach and trim them and trim the plants too
I do have slime still on the walls of the system when I reach inside I can feel it.. I guess I will take the unit in the shower and hose it down and start over without any organic stuff like vinegar.

for Nutrient I decided to go with Dry nuts in parts so I can adjust it as time goes on and I get experienced..

I got Hydro Gardens (chemgro) in Colorado Nuts.
Got their Tomato mix 25lb, Calcium nitrate 25lb and Mag Sulf 15lb

Chem-Gro N P K
Tomato Blend 4 18 38
Calcium Nitrate 15.5-0-0

final mix is something like this
Tomato Mature 10 9 19
1/2 Tomato+ 1/2 Cal-Nit + 1/4 Mg- sulf

comparing to Maxi Gro 10 5 14

for the past 3 days the system is running on just water with PH adjustment.. was wondering if I could get rid off the bitterness in my basil plants...

I have some new plants that will be planted in there soon

Albion Strawberry roots
Sweet baby girl red cherry tomato
Sweet sun yellow cherry tomato
Mohawk Dwarf Orange bell pepper
Lettuce leaf Basil

I know these are hard to have in the sam system but I want my herbs and I wanted to try small tomato and pepper in there and try to find a medium to keep them going till I add a second system for the nutrient hungry plants.

Oh my tank is just 5 gallon and yes I know it is tiny lol but it should do the job till I am ready to upgrade..

Perhaps I will add an airstone to increase the dissolved oxygen.

    Bookmark   March 25, 2014 at 12:55PM
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PupillaCharites(FL 9a)

Very nice! Looks like you're also a graduate of the school of Bobbyponics :-). Don't worry about attempting that Maxi Grow calculation comparison. Right about separating the plants into 2 systems. Sounds like you are all set with what to do. I think it's time for a good salad and a new start, don't you!

BTW, Love that mirror. First I thought you had two systems. Also, it's probably there just for the picture, but you might be better off storing your fertilizer mix clear plastic containers in a very dry, dark place away from the humidity right under the tower!

Best luck and congrats, even with the little setback it is really looking sharp. Very nice craftsmanship to be proud of.

    Bookmark   March 25, 2014 at 1:39PM
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doctorman(7b / indoor)

Thank you.. it took a lot of work but it looks nice.. and it is in the beta testing now and hence the mss up

took the whole thing apart as we speak and there was tons of build (mother vinegar slime) and bunch of undissolved solids that possibly was causing the PH going cuckoo

everything part is being bleached and scrubbed getting read for round 2

the plants roots is not that bad now that I took it out.. it seams like there was a root rot that plants came over.. o there is a big moosh of dead black roots and new white roots growing around and out of it..
cleaned the roots under high pressure water as much as possible and put them in a bath of H2O2 till the system is up and running shortly..

any guidance on the nutrients? for this system?
some sort of universal mix acceptable to most the plants I will put in the system is what I am going for till a 2nd system come about..
and I will update this post tomorrow see how my PH is holding after a deep cleaning.

    Bookmark   March 25, 2014 at 2:19PM
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PupillaCharites(FL 9a)

Actually your nutrients are ok If you are using the 12/12/6 makes 30 grams per 5 gallon bucket ==> indoors.

I think you are in the multipurpose region, with an average of strawberries and basil, though I don't know how much calcium is in your water. you go outside though if it is dry and higher altitude, and you might cut back on the nutes anything from 20 to 40% depending, cutting back more the more the plants drink. How much they drink vs how much is lost to evaporation from the netpots and crevices is your guess, so that will be a little experimenting.

I feel sorry for the roots soaked in H2O2, it's like someone telling me my little girl fell in the mud and school No more comment on that since I am a card carrying member of Ppl for the Ethical Treatment of Plants and yet others swear by bleaching roots and systems all the time and are growing good stuff.

This post was edited by PupillaCharites on Tue, Mar 25, 14 at 16:23

    Bookmark   March 25, 2014 at 4:12PM
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doctorman(7b / indoor)

I am not sur eI understand what you mean by "using the 12/12/6 makes 30 grams per 5 gallon"

Tomato blend mix that I have is 4/18/38 mix half of this with half Cal Nitr 15.5/0/0
that makes 10/10/20

I will measure it for 3 gal instead of 5 and move up from there if I see deficiencies I guess..

I do feel bad touching the roots but you should have seen what a mess I was dealing with.. I am not very experienced but between H2O2 diluted solution & bleach H2O2 sounded not too bad..
I think I should trim the plants so the trimmed roots can support what is on the plant.

right now again the system is just running on filtered water (ran it through brita and adjusted the PH to 6.5..
and I am debating how much nutrients to put in..
My tap water as I said is medium hardness around 50 Calcium , 180ppm total solids and PH of 7.8

sorry my post was all over

    Bookmark   March 25, 2014 at 4:28PM
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doctorman(7b / indoor)

as I was reading I came across another issue that might be causing my root rot and bacterial growth, my indoor system will have indoor temp of 25C, that is a recipe for disaster.

I have lowered the temp by dropping in a frozen bottle of water daily down to 16C.

also adding some daily H2O2 should help

1.28*G/C= Liquid Oz's per day

c= concentration of H2Os 3%, 8% 35%

I will have the system run on this without nuts for a day and monitor the PH..

    Bookmark   March 25, 2014 at 6:34PM
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Hi Doc!
Your tower looks great!!!
Very nicely crafted.
Did you glue the pot holders onto the surface of the tower similar to the video, or are they recessed into the tower a bit?
I don't see any glue joints. Yours turned out much better looking then the one in the video!

I feel for you, in regards to the pH swings. I too had that problem up until last week. Switched Acid from lemon juice to nitric acid and also switch nutrient formula. Rock solid at pH6.0 now. It was swinging up to pH8.0
I would drop it down to pH6.0 and with in hours it was back up. Also had the sludge problems in my reservoirs. It was very frustrating and discouraging.
But all seems good now.


    Bookmark   March 25, 2014 at 7:40PM
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doctorman(7b / indoor)


Thanks for the comment,
I used white PVC cement to glue the holder to the post
took more work but final product looks neat, also I cleaned all the writing on the PVC pipe.. that took a lot of time too but it was worth it.. I needed the device to look beautiful so my wife is happy with the mess I am making in the house lol

which nutrient are you using now that solved your problem with the PH? I know the more expensive liquid nuts are buffered.
It does not make sense to me why the PH goes crazy..

do you have a raintower setting? would like to see pics..

doesn't nitric acid increase your nitrogen?

I heared the right solution is sulfuric acid and maybe some phosphoric acid..

    Bookmark   March 25, 2014 at 10:02PM
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Hi Doc,
i currently have three 5 gal-20 litre bubble buckets and a 4'x3' flood and drain table. tomatoes and strawberries in buckets. Lettuce and strawberries on flood table.
I switch From DNF (Dutch Nutrient Formula) to Dutch Pro.

See my post on yellow top leaves to see pictures of the buckets and to see what happens to tomato plants when the pH gets above pH7.0

I'm thinking of making a tower for outside.
I don't think they would work very good indoors with t5 lamps.
florescent lamps don't have enough light penetration like HID bulbs do. Unless of course the fixtures are mounted vertically all around the tower and the shins towards it from the sides as apposed to from above.


    Bookmark   March 25, 2014 at 10:31PM
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PupillaCharites(FL 9a)

Hi again ...

Ok oops, I assumed you were using a scale to weigh your three part fertilizer salts, and since it was 5 gal, that you would recognize my 12/12/6 as 12 grams fertilizer, 12 grams CAN, and 6 grams Epsoms. It wasn't about whatever the NPK is, just the weights of each you toss into the res.

I just read you said, "I will measure it", and that should have tipped me off because you said "measure", not "weigh" as I would have. Maybe you are using teaspoons and that is what you are talking about, so I'm gonna guess the 1/2, 1/2, 1/4 are teaspoons per gallon. I just took them as mixing weight ratios, because I think in weights, because you never mentioned grams, teaspoons, gallons or anything, just the fractions. Sorry for Assuming!

So let's compare the 12,12,6 in grams/5 gal with the 1/2,1/2,1/4 teaspoons per 1 gal and see if we're talking the same thing before the assumption gets anything messed up.

yours is 2.5,2.5,1.25 tsp (6.25 tsp total)per 5 gal
mine 12,12,6 grams (30g total) per 5 gal.

Bulk densities ag (approx):
Epsom salt: 1.0 g/mL
CAN: 1.05 g/mL
4-18-36: 1.0 g/mL (KxHxPO41; )

so, we can be pretty close and say these powders are all 1g/mL, just like water, which means (1 tsp=5g):

yours is 12.5,12.5,6.25 tsp (31.25 tsp total)per 5 gal
mine 12,12,6 grams (30g total) per 5 gal.

conclusion, 6 of one and a half dozen of the other (basically, same same)

Hope I haven't confused you, and it will be funny if you are using grams, but it sure doesn't sound like it. Anyway that clears up what I was talking about and is good to read over to change yourself over to using grams on a scale (ten buck's investment, good to the tenth of a gram) which will make your results much more repeatable when you mix, and is pretty useful if you are going to improve on your methods since with weights there isn't the uncertainty of guessing when the tsp is full or settling the same.

    Bookmark   March 26, 2014 at 1:43AM
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PupillaCharites(FL 9a)

Your water sounds like excellent water btw. and the fertilizer is dependable, inorganic. With all that crud in there plus vinegar, I'm sure now that you've fixed it you will have no problem (fingers crossed) by adding the aeration. I hope you can keep it. The filter you're using is removing most of the chlorine, which is probably helpful, and will be necessary for the strawberries. But it didn't help clean out the microbes that grw ;(. Great you are cleaning up, though I really don't go for that H2O2. 25C is a bit high, but not a dealbreaker for basil and herbs.

It would be best just to put a bubbler in there, though the ice bottle is really great, keeping the bubbles going when the system is not dripping will help stir and aerate whereas the temperature won't be very helpful if there is no action. I don't think it is much of a problem for the plants though because the nature of the vertical dripping will provide penty of aerated water to the roots, I think, this desighn is very good for that and shouldn't suffer the drawbacks of a DWC.

How much water were you loosing in the reservoir, through the plants and by evaporation combined, on average in a week? If you are starting over with small plants sort of decent seedlings half strength is a safe bet, and depending on how much loss we could adjust between 70-100% of your current nutrient strength. If you're in a usually high and dry climate, like Reno Nevada vs. a usually low and humid one like Norfolk VA the amount of solution going through the plant can be so different.

If you are keeping the peroxidized rooted plants in there it is going to be hard to say this time much since we don't know how far you are being set back from them vs. what the fertilizer should do.

    Bookmark   March 26, 2014 at 2:50AM
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doctorman(7b / indoor)

I was reading about the PH buffer with citric acid
potassium carbonate, sounds tempting. if I have not bought over 2 pounds of the GH PH Down Dry I would give it a try but for now lets see how the system will hold.

All my measurments are in Tsp according to instructions from Hydro-garden
Tomato mix:

mixing instructions:

MSDS sheet :

I lose around .7gallon a day in this system with the 3 plants in there.
Oh when I was cleaning I took out all the netpods and hydrotons and soaked them in PH of 2.5 just to make sure they do not increase my PH..
I will measure the PH in the morning and see if it is stable
if it is I will add enough nutrients for 4 gallon (not 5 to count for evaporation)
if in a week or so my system is still moody with PH I will order the buffer stuff and try that.
Dry nut. is easier to store and cost so much less than liquid. beside the fact that I spent 100$ on the nut and it is enough to last for many years I will try my best to learn to use this and buffer it.

P.S> I am in zone 7b NY
but again this is indoor

    Bookmark   March 26, 2014 at 3:16AM
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doctorman(7b / indoor)

Good Mornin!

So this beautiful spring morning with outside temp still in the freezing 40s we go on with the PH quest of mine lol

yesterday I adjusted the water down to 4.7PH (the ph down solution slipped form my hand) but in 2 hours I was up to 5.1 (this is JUST water)

this morning I am up to 5.2 which is nice.. generally my PH would have been 7-8 by the morning check
unfortunately the water does run warm and the ice melts quickly in there. so I fill ziplock bags with ice and dump them in there.. down to 20-22C from 26C

I drained the water in to a bucket and added my Nutrients

Starting water now is at 22C , PH of 5, 220PPM

Hydrogarden Tomato mix 2 tsp + Cal Nit 2tsp + Mg sulf 1.3Tsp
mixed it for 15 min

poured it back into the system added some ice bottle and H2O2

after mix we are up to 920ppm. PH 5.2, temp 21c..

I can not keep up this temp control I will see if I can find a cheap chiller.. open to ideas on this.

I will let the PH ride at the low 5 and see how it handles itself in a day..

P.S. the mix is Derived From:
Potassium Nitrate,
Potassium Phosphate,
Muriate of Potash,
Iron Chelate (DTPA),
Boric Acid,
Iron Sulfate,
Manganese Sulfate,
Copper Chelate (EDTA),
Zinc Chelate (EDTA),
Zinc Sulfate &
Molybdic Acid .

    Bookmark   March 26, 2014 at 10:38AM
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PupillaCharites(FL 9a)

What's the air temperature of your house a yard away from the reservoir bucket? What is the wattage of your pump?
4 gallons is simply not much mass of water to diffuse it. I suggest you forget about the water temperature and just you aerate it with a good bubbler. The bubbler will have a cooling effect as well. If you want to drive your wife's patience and do more work, also just double the size of your reservoir. You can always use the present reservoir for your second tower.

I don't know what more to add about the fertilizer since teaspoons is to crude of a measurement, and I'm too busy to deal with ppm instead of EC, but it sounds probably perfectly fine and you just need to get more comfortable with adjusting your pH first ;-) which you're experimenting with to do that already.

    Bookmark   March 26, 2014 at 11:40AM
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doctorman(7b / indoor)

Thank you PupillaCharites..

you really helped me out getting to the bottom of this

as mentioned I put an air stone in there since yesterday..

The house air temp is around 26c or so.
The corner that I have the tower in gets a bit hotter because of the light right on top of it and not much air circulation (I might add a tiny fan in there later)

I see there are aquarium chillers for around 100$ that should do a nice job.. it is good to know that I have that option in case I need it. I want to avoid problem and make it an easier system to maintain since soon I will be very busy again with work..

I hear you about measuring out the weight but I dont think it makes a difference.. I will weigh what I poured in the system and report here as a reference.

    Bookmark   March 26, 2014 at 12:21PM
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I`d check the air temperature inside the tubes, if its excessively hot the roots will turn brown and start to decay.

    Bookmark   March 27, 2014 at 2:58AM
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doctorman(7b / indoor)

Day 2 since the transformation..
the PH is climbing up very slowly
Started at 5.2 and we are now at 5.8. I am happy with that.. 2 days and PH is still below 6!

for water temp: I covered it with bubble wrap just one layer and it keeps the temps now close to 20c.
I would not bother with chillers at such temp. maybe just a tiny Thermoelectric Cooler (Peltier pump) just sitting on the surface of the plastic bucket with a heatsink.

The air temp inside the post will not be the correct representative of the roots temp, the roots will be coolled by evaporation during the 15min off time of the pump.

    Bookmark   March 27, 2014 at 7:49AM
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"The corner that I have the tower in gets a bit hotter because of the light right on top of it and not much air circulation"

You need airflow for evaporative cooling, the air inside of the tube needs to be low RH or the water cant evaporate. Worse case is the water will stay on the roots and warm up in the 15 minutes the pump is off. I guess you`ll cross that bridge if/when you get to it :)

    Bookmark   March 27, 2014 at 9:38AM
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doctorman(7b / indoor)

house temp 27c
inside the tower air is around 24c

you have a point for sure.. but there are many holes and hydrotons get wet and evaporate on the outside that cools the inside.
I will keep an eye on that
thank you!

    Bookmark   March 27, 2014 at 10:24AM
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PupillaCharites(FL 9a)

hex, Unless he has a puddle on the floor, 0.7 gallon of water daily was evaporating through his tower when only 3 plant spaces are taken. However or wherever that water is getting out I would only be able to guess, but 0.7 gallons is an enormous amount of evaporation given the reservoir and house air are nearly the same temp. And that was before the airpump was put in. Sounds like the house has low humidity with a heater maybe responsible for that, so some fun probably is ahead.

doctor, Unless the thermoelectric surface is set into the outer surface of the reservoir bucket with a fan, you are more creative than me with it, I'd keep it simple, and maybe it will be fun for you to try. But I'd just put a small computer fan mounted to blow away some of the heat outside by the light unless there is already lots of air moving around there.

Sounds like you licked to pH problem to me! I bet you appreciate to slow steady pH drift now 100X more since you had the opportunity to suffer with pH before;)

    Bookmark   March 27, 2014 at 10:37AM
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doctorman(7b / indoor)

PC, I sure do appreciate the PH very much now!

I am still debating if I should add the thermoelectric cooler.. and yes it would go on he outer surface of the reservoir bucket with a fan.

P.S. since I added the bubble wrap around the reservoir and added some iced bottle in there my evaporation has been halved ..
and my water is clean and clear..! I assumed it is supposed to look like $#!t with the nuts lol damn you bacterial growth!

love it!

    Bookmark   March 27, 2014 at 11:00AM
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doctorman(7b / indoor)

Update 6 days post clean up:

PH stable at 6.1
planted 12 Albion strawberries in there 2 days ago and they are already growing by the hour. the water is still clean and clear. 2 gallon evaporation in 6 days, PPM went up to 1100ppm so that means every 7- 10 days my system will need a water refill and probably every 3-4 weeks complete water change to balance the nuts.

Keeping the temp down works fine with daily frozen water bottle but it is a pain, at this point I don't think it is that important to chill the water specially with the airstone in the reservoir bubbling away but if I can come up with a cheap chiller solution I will go for it..

Thank you guys..
I will post pics of my system soon with the strawberries in there .

    Bookmark   March 30, 2014 at 2:27AM
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