Reverse Osmosis Calcium Supplement for Tomatoes

widespreadpanicMay 2, 2011

I'm using RO water b/c my tap water here on the coast is no good.

I do not want to use half tap half ro water.

I plan on using Hydro-Gardens 3 part nutrient solution.

To make 100 gallons of nutrient the following recipe is used:

1/2 lb of chem grow 4-18-38

1/2 lb calcium nitrate

1/4 lb magnesium sulfate

My question is, do I have to add calcium in the form of calcium chloride or is there another way? Its all rather confusing. I used to use general hydroponics Floramato but found it unsatisfactory so I'm going with the Chem Gro this year.

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Not sure I understand the question. Why would you need to add calcium in the form of calcium chloride when the directions call for calcium nitrate?

What was it about the Floramato that you didn't like.

    Bookmark   May 2, 2011 at 3:53PM
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Well, the instructions from their website says


"If the calcium level of your source water is below 50 PPM, you should add 1 ounce of Calcium Chloride, (or 25% of the weight of Calcium Nitrate that you are adding) per 100 gallons of working solution, in with the calcium nitrate until you have increased your calcium levels to full strength. This will supplement the calcium levels in your working solution without increasing the amount of nitrogen to your seedling plants."

I was thinking since I'm using RO water with 0 E.C./TDS reading, then I need to supplement calcium per instructions.
Or do I?

I dunno, was thinking maybe someone out there has heard of or used a 3 part solution with RO water that could guide me.

NOTE: After the original post I found food grade hydro Calcium Chloride, it's pretty cheap so I guess I'll follow the instructions and see what happens.

What I didn't like about the Floramato: It's designed for "Tomatoes, cucumbers, eggplant, peppers, melons, beans, strawberries etc." Its more of a general purpose hydro mix, but I'm only growing tomatoes.

The reason I used it last year was b/c it was the closest thing I could find for a hobbyist tomato grow. Upon further research it seems as though it is inadequate for a tomato grow. I also feel like the nitrogen levels were too high for tomatoes, but I'm not sure about that.

Another main reason to change is that the Chem-Grow is approximately 1/4 the cost of Floramato.

Here is a link that might be useful: The Greene Tomato

    Bookmark   May 2, 2011 at 10:34PM
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turns out the calcium chloride supplier is in toyko and doesn't ship to the U.S.

It seems like the chlorine addition via calcium chloride could be bad?

If I use reverse osmosis water, would it be ok?

    Bookmark   May 2, 2011 at 11:27PM
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I use GH 3-part along with additives. I use cal+mag from gh other brands makes it aswell. It suits my cherry tomatoes needs.

    Bookmark   May 3, 2011 at 1:16AM
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I use Floramato with great results. I used it on Brandywines and Yellow Pear tomatoes. Both are indeterminate and went absolutely nuts. Keep in mind that calcium deficiency is usually not due to your solution having a deficiency. It's usually a matter of inhibited uptake. Adding calcium won't help you there.

Also, I use rain water for the most part - on par with R/O when it comes to calcium content.

I'm fairly convinced that Floramato is as close to tomato specific as you will find. It might be functional as a general purpose, but that's because tomatoes have such high demands and it will work for all those others that don't require near as much. If you want to get more specific to their needs, you will be best suited to learn to make your own nutes, in my opinion.

I've used 3 part nutes. I've used all in one nutes (like Botanicare). So far, Floramato and Maxigro have worked out quite a bit better and are much cheaper.

    Bookmark   May 3, 2011 at 12:02PM
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If you have calcium nitrate and mag sulphate on hand why bother? Tomoatoes won`t mind the additional sulphur from magnesium sulphate. Most of the commercial calmag`s use calcium nitrate, magnesium nitrate and chelated iron so the N in yours will be lower because you`re not using mag nitrate :)

    Bookmark   May 3, 2011 at 1:35PM
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Thanks for the replies.

Joe, Last year I used town water that was borderline questionable for hydroponic tomato production. I sent it off to my NC State University and the results weren't great. I live here at the beach and we have high sodium etc. etc.

This year I am starting my grow with floramato but will switch once the other nutes arrive from hydro-gardens.

Point of fact, I am looking for a calcium supplement not b/c I am showing a deficiency, but b/c nute manufacturer calls for the supplement if your starting water is below 50 ppm calcium. My RO will be.

Joe I used floramato last year and my brandywines did great as well. But, Floramato is expensive, the best price I can find is 114 bucks for a 14 lb pail. And while they did great, it was my first grow so I am skeptical about whether or not a tomato specific nute will do better than Floramato.

What did you run your E.C. using floramato last year? Just curious b/c all my hydro tomato books call for at least an E.C. of 2.4 but my plants never seemed to want that much.

Here is a link that might be useful: My hydroponic tomato blog

    Bookmark   May 3, 2011 at 2:18PM
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I never go over 2 anymore. I keep it around 1.6-1.8 for the most part. That's using the rain water.

Have you contacted hydro-gardens to get suggestions?

Maybe you could try contacting Daniel via his website (which appears to be upgraded since I last visited it).

Whatever you do, please keep us updated. Actually, I don't get on here often anymore. If you don't mind, let me know how the nutes work out via email. . . is checked regularly. It's also my name on google talk/chat if you care to instant message.

Here is a link that might be useful: Daniel's site

    Bookmark   May 3, 2011 at 5:06PM
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Will do Joe, thanks for the input. I'm also very interested in your apparent hard work making the nutrient calculator.

I'm gonna check it out for sure! Have you thought of putting it out into app form for cell phones? Just wondering?

Here is a link that might be useful: My hydroponic tomato blog

    Bookmark   May 4, 2011 at 12:01AM
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That's not me. That's Daniel that did that calculator. It is pretty awesome, isn't it?

    Bookmark   May 4, 2011 at 9:13AM
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If you plan to use reverse osmosis water but want a calcium supplement, you can use a filter called a calcite filter as a post filter.

Here is a link that might be useful: calcite post filter for reverse osmosis

    Bookmark   December 8, 2014 at 3:33PM
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