I would just do small water changes, use no chemicals [just clorine remover or let water sit for 24 hours] and wait. If the ammo is dropping thr nitrite will follow, you should just wait for it to happen. Big water changes and various chemicals could alter or even kill the growing bacteria. Patience is the key.

I agree with James. Cycle and some of the products you mentioned will alter your nitrite readings as well as pH. Just use a quality water conditioner that will detoxify chlorine as well as ammonia and chloramine,nitrites and nitrates. Aquarium salt is good to help new fish or stressed fish it also will block nitrite poisoning when levels get to high.
Ph, How low is too low? What is your pH level without adding any chemicals? Let a sample of tap water sit out overnight. Check the pH of the "aged" water sample. This will be a more accurate pH level check.
The thing to understand when starting the new tank is you need to see the ammonia rise then be undetectable. When the ammonia is undetectable the nitrite level will spike then als become undetectable. When these 2 things happen your tank is considered "cycled". If you don't allow these 2 things to happen your tank will not cycle. Don't clean or replace the bio-wheel or other filtration cartridges when "cycling" If they become clogged for some reason, only swish them around in conditioned water to remove enough build up. Save your money on Cycle and the other products that are supposed to add beneficial bacteria. They usually cause more problems then help. You can change up to 50% of water (without chemicals except conditioner) at a time if that's what's needed. The only reason to do water changes is to dilute extremely high levels of ammonia or nitrite. When the tank has established a cycle you just need to do PWCs for maintainance.
If you haven't added fish to your new bigger 37G consider a fishless cycle. It will take about 4 weeks +/-.

To conclude: Last first.

To much commotion in the ocean, lol.

First, what is your actual ph? Bettas can like it lower then 7. Unless your ph is say acid of 5, I would just leave it alone. If you do need to raise it (and unless your water is buffered correctly it will sink again) ie water hardness, you can add baking soda (what you are buying anyway basically, or a pinch of coral).. but then you have to watch for swings in such a small tank.

Natural Habitat: Occurs in standing waters of floodplains, canals and rice paddies; benthopelagic; freshwater; pH range: 6.0 - 8.0; dGH range: 5.0 - 19.0; climate is tropical, with air temperatures ranging from 24 - 30C. Water conditions in habitats is often oxygen depleted. The air above the water is always warm and humid.*

* another reaon for lids, and water line a bit lower, humid air is needed.

As long as you do not shift ph more then .5 per day (causes osthmotic shock in gills) (bettas less so, but still I have not checked ph in holding tank (city changes municiple supply or it rains) and was huge shift and betta sank (even with slow dribble) and took a day to recover. Other smaller fish will die. So one must check ph and do gradual changes. If you have low ph, say 6 or so, just use that. They in the wild come from all regions (some cooler rivers even) but these are bred for generations and more tolerable.

Emergancy fix.

Put your betta in a bowl with lid. Hole in top and space to breathe. (put in another larger bowl with lid and towel so as not to stress him. Lightly clean out your tank for him/her. (any scum so on) but don't disturb any bacteria/filter.

(I would highly recommed not to use sand or planted plants in such a small system). Use floating like Annubias (barteria can ussually be found, or that bunched type ( for get name of it, but bog plant, which last a few weeks)or what ever you can find and grow in lower light tank (Anubias is superb). With bunch, cut off tied ends and float. They will love it. Much easier to clean and plants add so much with filtering, and small things bettas nibble on.

Take water from your already established tanks and put into your betta tank.. Maybe not all the way so can add fresh to it as well. (add fresh after betta is acclimated (see below) to this 'new' water, with same slow drible method (whatch for jumping always, you will be suprised (I've had one gal jump three times through small grid, had to stand by and watch and put wet towel around tank even then.)

Now, so as not to shock betta, slowly add this new water to his holding tank. Do it with a (turkey baster) or I take some out (they panic with small amounts of water hence the double bowl and lid (ie jump). I use the plastic light grid over bowl, and filter water back in with small hole in plastic soup bowl (chinese plastic soup thing)... a small, slow dribble. Watch at all times, mine have pushed lid off and jumped out. (hence lower lights as well). Eventually when new water has replaced old, gently put betta in new water (from established tank) tank. This should be ample, about 2/3ds. Then fill rest slowly with fresh aged conditioned water. About 1/2 to one inch below water line.

(Plants in there as well will help plus they like to hide, nibble, and rest on them - butterflys of Asia.)

*I am esp gentle with my bettas (all fish) and acclimate them really slow just from my experience. Helps to avoid shock and disease later.

Add some used (but not really crungy) filter floss from the same established tank you got your water from, can rince in tank water if need be, to your system, squeeze it in somewhere to add bacteria to your new set up (I pack my own system = cheaper, but now just use the penn plax filter, more gentle flow for betta.)

You can use gravel, stones or wood or anything that is in an established tank, but floss best. Bacteria on everthing.

This will instantly cycle your tank and you can avoid all that you are doing. (remember slow acclimation, new water is not same as established, not just ph, but bacteria shifts can shock fish as well (found out hard way).

.....................................
SNAILS - the hidden culprit. I think they are your main problem here.

Snails produce tons of waste and my own experience is to do without them, esp in a smaller tank. I had trouble and once eliminated (one large mystery snail - and all others) huge improvements on water quality. And they poohed so much in 3-5 gallon tanks for bettas, even with filtration and plants caused many problems. when I did a complete tear down (saving filter and some water) I was shocked at how much pooh, even though I have little sand, and vacume clean or syphon if in small tank at least every other day. They just crxp a LOT! That will raise nitrate/nitrite/ammonia. Especially when you are just setting up, like overloading new set up with too many fish, they pooh much more then most fish. I liked snails but found they just create too much waste again esp for smaller tanks.

(also check your feeding. Betta stomach as big as eye. Feed food not so dry (gets constipated) and I feed one or two bits. Any at bottom will create spikes inbalance esp in newer tank.)

If you have already established tanks, use filter floss for new one when you set up new tank in future. I cycle tanks in one day (do not overload with fish) with this method. I have two filters per 20 long, and now one with bio and other sponge. So it's easy to take out small sponge filter (penn plax now makes one) and use it to set up new tank.

Remember the Eclipse or other tanks with built in systems, may have water flow too fast for a betta. I put a sponge filter thing on intake and some silk leaves, sponge or what ever at the outtake to reduce water flow.

I've also noticed that smaller more frequent water changes are better (think nature which changes water all the time (unless stagnant pond)... but esp in the smaller tanks. It causes too big a shift in bacteria, ph, other things. In my smaller betta tanks (fully set up 2.5 on up gallon, room warm so no heater) so you are essentially starting over each time you do a bigger 50% change which is way too much except in emergancys (then go back to top with emergancy - I have found having an established tank the best resource for cycling)

I do even once a day if bottom looks cruddy (to me that is one pooh, lol) and I feed sparsley. Only an inch or so of water out. Drain it off (no sand) and I have that light grid, which I put on top, fill my bucket up with aged filtered water, then use those small plastic tubs (like when you order chinese wonton soup) poke a small hole in it, then fill it up with water, set it on grid and slowly add water back into the tank to avoid any sudden shifts. You can add a silk or real plant leaf to calm betta.

For my bettas I use this smaller filter (penn plax) which also has amnonia chips in it. I get a valve (those teal colored valves) to reduce water flow (betta fins one cell thin so can tear easily) and or you can move the filter to the top of the tank (glass lid of course).

I add always plants as bettas love them, and it is easy with any type of Annubias (don't bury rizome) (forgive spelling)so can tie to wood or I just let float. They help with keeping water clean as well. This creates real dimension and Mr. Betta will go all round, and be lively and creative (ie not bored) during his day.

I do small water changes in my 2 -3 gallon every other day just poo off bottom. Actually sometimes daily. Any less and bacteria problems down the line. The smaller the tank the more imbalanced and harder to balance so hence mechanical balance vis a vie water changes. Smaller more frequent means less stress. Nature has huge water systems.

I feed small amount of frozen, once day or live worm so on and vegetable (pinch) evening (to help with constipation) early evening. (I caught a moth once, and before I could barely hold it over tank betta jumped out and grabbed it. (What we feed them must taste like ugh to them. At some point I hope to raise live food as I did when younger.)

TIP: If any fish is constipated, add cod liver oil just a touch on pea or whatever - whammo!

I add salt, about 1/4 per gallon (I found aquarium even though some say it can't raised my ph. The Kosher which is pure sodium did not. (I tested all types and Kosher was only one that did not) (and if sick bettas can tolerate a lot as long as you build gradually, and same in reverse when post sick and returning to normal levels.) I did this as a child long ago per Dr. Innes books, and still use it and works against Columinaris Bacteria for instance better then meds). (I have also been adding those leaves (forgot name for now) that breeders use to add tanin.

I agree with all above, you will make a mess with additional chemicals (save for water conditioner). (there are links for this, it really creates havoc in the end. I do have a great bio powder I got ages ago (still viable) and rarely use it only for when if I ever have to tear down a tank (get rid of snails coming in from plants, rare now)

I prefilter and age my water, this makes it real easy (I have to filter, nasty NYC water) But you may just age it (ie get a garbage or plastic tub and have water in it to same temp so on. Filter it if it is needed or not used up in a day or bacteria start up).

Penn Plax Smallworld Filter

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(most pet stores carry the smaller filters now) I change them once a week. Or rince if tank not so dirty (less fish) and change less often. Remember charcoal once it absorbs will start to release toxins. So I just change once a week.

Remember, sometimes less is best.

Lower ph is ok at least 6. (but not for snails, any snail, they need higher ph or shell will disolve, ie calcium leaches out of shell into water, good for water bad for snail).

Cycle with established tank filter floss and water.
Get rid of snails - trust me on that one (and if ph lower will kill snail in end, you will see the shell thin away, although some feed with calcium blocks). (lol)
Plants.
Filter either smaller slower one, or make sure sponge over intake, something to reduce flow at outtake.

Smaller more frequent water changes. Breeders do once a day in their one half gallons. Add water gradually to accomodate any ph, et all shifts.

In smaller tanks I do good water cleaning once a week. I take out part of water put betta in it, plants so he won't get scared (towel on top) and put aside where he won't get accidently knocked over. Clean tank and put most of his water in with him, then dribble rest as fresh. do not tear out all of filter or will have to recyle. (that is why sponge over intake is helpful as well, just rince in old tank water before dumping in drain. I just never have a cycle problem anymore or really ever did.

(when treating sick fish, I used for small fish, 2.5 gallon and change water daily regardless of instruction. Most meds are too low a dose and non pharma grade (fillers) so pharma grade. I have been using less toxic means, garlic, HY20, other herbs, salt is life saver for many things (back ground in pre vet/ocean sciences, and nutrition and natural methods, used on me, my cats now with fish, works better in many instances. instances)

As a kid never heard of any of this (neighbor got me started with her small narrow guppy tank full of small sagitarius, sans filter, heater et al. In back room with dappled sunlight and lived in balance for generations.) But per my librairy books, one was to set tank up for a month or more and add fish gradually. (same thing, lol)

Best to you.

You will see, doesn't need to be so out of balance and difficult.

(my ph is super high and hard (water has lime in it, and before was super low (5) It can start low, then shift high, so am trying adding carbon to keep it lower for plants only as fish I have are fine with 7.6. (most just won't breed if they need softer water). (I could have had chiclids all this time) I was adviced here and elsewhere, to just leave it alone. Even my tetras (not neon or wild caught anything though that needs lower ph) do just fine after many years. Most are commerical bred and adjust to this water.

Bettatalk is great breeder site. (sorry for mispellings and ramble very late here)

Thanks for all the advice!! Over the past few days my nitrite levels did drop and looks as though my small tank is just about cycled.

Now I'm dealing with my 37 gallon tank. I've had it for about 4 weeks and presently my ammonia is high and my nitrite is just beginning to be detected. I'm doing small water changes unless levels are extremely high in which case I'm doing a 50% change. I have lost 2 fish so far, one Julii coreycat and 1 sunburst platy. These fish were a little weaker when I bought them and couldn't handle the levels. I currently have in this tank 3 red wag platys, 1 gold mickey mouse platy, 3 spotted corey cats and 2 julii coreycats. I also have 3 babies of the mickeymouse in a breeder that were born about a week after I set the tank up. I now regret adding so many fish to a new tank but the people at the store said Platys were so hardy and coreys were too. I'm doing the best I can now with what I've got.

Here's my question...both my tanks have next to 0 alkalinity and sometimes the PH is lower than 6.4...I don't know what because my strips don't go down that low. My water hardness in both tanks is also on the soft side (around 50 for the 37 gallon). I love my snails so I think I will move one to my big tank to cut the waste a bit. You said the low ph will hurt them and I know Livebearers (my platys) like right at or a little above 7 ph. I've been adding "PH Up" which works for a day or two but because my buffering is so low it doesn't stay there. I know they make "Buffer Up" and some like products to help with this but I cannot locate them in any store near me. Any suggestions? THANKS

Yes save yourself a ton of $$$ and buy baking soda. Usually pH up and Buffer up products are sodium bicarbonate (baking soda) or calcium carbonate (sea shells etc.) or even calcium chloride (ice melting beads). Anyway for the 38G us about 1/2 tsp. and check the pH after 2 hours and adjust.
The key is what is your tap water level? If your pH is crashing in your tank, but your tap water is normal (after aeration or leaving it out over night) then the culprit could be:

1. ammonia level. high ammonia can cause pH to crash.
2. a chemical you are adding. I know that regular Amquel will crash pH in soft water. You mentioned that your hardness was 50. The other crap like cycle also can cause this. It's just better to avoid these chemicals. The less stuff you add the better. Nature creates most of the chemicals you need once the tank establishes.

If your tap water is acidic after aeration and soft both GH and KH, consider yourself blessed. It is much easier to make soft acidic water neutral pH and ideal hardness then the other way around. To correct acidic water use the baking soda (B.S.) for water changes and short term effect. Place seashells, limestone,or marble as decorations or get some crushed coral from the pet store and put a few scoops in a media bag in your filter or mix some with your gravel. This will raise pH as well as KH. To raise GH use epsom salts (magnessium chloride). These remedies are much less expensive and easier to use then overpriced pH up and other adjusting chemicals for aquariums. You may even have them around the house already.
The fish deaths when establishing a cycle are part of hobby. That is why I always reccomend the fishless cycle to people who are bothered by watching once healthy fish die from toxic water poisoning. Hope this helps, good luck.

I would just let the tank cycle, don't mess with the ph. I believe ammonia is more deadly the higher the ph goes. Big water changes will slow down the cycle. After the tank is cycled with zero ammo and 0 nitrite measure the ph of your tank water against water coming out your tap. If your source water is low ph there's really nothing practical to do except get fish that like a low ph. Keep in mind fish can adapt to a wide range of water parameters.

Ammonia is definately more toxic at higher pH. If nitrite is just begining to be detected the ammonia levels should drop with in the next couple days. Thats where it is NOT good to have a low pH. This produces nitric acid. Changing water to dilute the ammonia will slow down the cycle somewhat. When cycling with fish 1 ppm - 1.25 ppm ammonia is target area. Check out the link with these tips for your situation. There are some important factors to remember with this. Tests can easily be skewed and really have you chasing your tail.