ph not stable, help!

Hello, I use RO water I get from uncle bills that is ph 7, kh. 3 gh 3. After 20% water changes the ph is 7, a day later it's 7.4.. how can I stabilize the water at 7 safely? Also all that's in the tank is coated sand that said it won't change ph, a piece of cholla wood and live plants.

1 year old tank
10 gallon
1 male betta
2 nerite snails
a few ramshorn snails

20% water change every 5 days

Ammonia 0
Nitrite 0
Nitrate 5

 

Welcome to fishlore! CindiL can help.

 

Thanks: )

 

Hi, welcome to fishlore

I would not try and aI'm for a certain ph. 7 or 7.4 either are just fine. Fish can adjust to a range of ph between the upper 6's and lower 8's just fine. What's more important is the stability of your ph vs the actual numbers. Your KH is a bit low and will contribute to a fluctuating ph. I would add in some crushed coral to your filter in. A media bag to increase your KH and stabilize your ph..

 

Hi, Thanks for the help. I have a male betta in this tank and when I bought him he had fin damage. I drip acclimated him slowly first to my tap water. The fins were even worse the next day. My tap water is rough at ph 8.4, ammonia .O5, nitrate 10 ppm. I have had no success keeping bettas. Anyway, I bought the RO water from uncle bills, they said I didn't need to add anything. So I got home and slowly drip acclimated him to the neutral RO water in a 1 gallon plastic container. The next day there was already improvement. I did daily 50% water changes and in 2 weeks all better. Then I put him in my 10 gallon with same water and a couple days later fin damage again. Ph tests 1st day 7, 3rd day 7.4 or 7.6. Why would this water that stayed stable in the plastic container, rise in my 10 gallon? Sorry so long...

 

I honestly don't think it's the ph that has caused any fin damage. My last betta lived for three years in my ph of close to 8.0. The ammonia though would definitely do it. Is your ammonia .05 or .50? Big difference, as .05 is very close to 0.

Fish cannot live in straight RO water long term and I don't know why anyone ever says they can..... . Even softwater fish need minerals in their water for proper osmotic function, not to mention water without alkalinity can easily crash down to 6.0, killing your fish as well as your nitrogen cycle. He got better from your daily 50% water changes which was the best thing you could do for him.

The easiest way to stabilize RO water is to add in something like crushed coral, or some sea shells, or aragonite or a piece of limestone, cuttle(fish) bone etc.
Your other choice is simply to mix half RO and half tap water, this is what a lot of people do for their bettas. If brings the hardness and ph down some but allows it to be stable with the minerals from the tap. You could mix up some 50/50 and see what you show for ph, GH and KH.

When you say you put him into your 10 gallon with the same water, do you mean the RO water? What is the substrate in this tank? Are there any other fish or just him? As for why the ph has risen it would either be due to the type of substrate you have or the fact that in this tank there is a filter turning over the water (I am assuming you have a filter ) which brings the water up to its "natural" ph by releasing and CO2 etc into the water. My own RO water comes out of the tap at around a PH of 6.5 and rises when aerated to 7.8-7.9.

What is your water conditioner? I would pick up Seachem Prime if you don't already have it. It will detoxify any ammonia in your tap water for up to 24-48 hours, giving your bio-filter time to convert it to nitrates.

Is your tank cycled or is this a new setup?