How can I know for sure what is causing my ph problems?

[Leopardfire]

I am starting a new 20 gallon tank which will have 4 cory catfish and one betta. I planted the tank and put in black Petco sand for my cories. When I tested the ph of the tank, it was at 9 which is way too high. It may even be higher because my testing strips stop at 9.
The ph of my other tanks with gravel is at 7.5 so the only thing I can think of that would bring my 20 gallon's ph to 9 is the sand. It is normal aquarium sand so it shouldn't cause this problem. Other people on here have used this sand without a single problem and they love it so I don't know why it would be different for me.
What can I do to know for sure if the sand is the problem? I spent $40 on it so I don't want to just throw it out only to find that it wasn't responsible for the ph spike. Is there anything I can do to figure out if there could be something other than the sand that is affecting the ph? Should I try emptying out my entire 20 gallon, rinsing everything off, and starting over?

[ChoclateBetta]

Is there anything like shells, or rocks they cause higher PH.

[whimsicalbrainpan]

Did you use tap water to fill your tank or bottled? If you use tap have you tested the Ph? Maybe you could scoop some of the sand out of the tank, put it in water you know to have a low Ph, and test it after the sand has been in for a while.

I wouldn't give up yet. I'd rinse and refill. I'm still kind of new to all this though, and some may have better advice.

[ChoclateBetta]

I think the test is the problem I would think the fish would have died in 9.

[DragonFish]

Yes, are there any shells or rocks that you put in there that could possibly affect the PH?
I have Petco sand in various colors in all of my tanks, haven't had any trouble so far....

I noticed you're using the strips.....might want to take a sample of water into your local Petco/LPS and have it tested with a liquid test kit just to double-check before you break down the tank or anything. Strips are known to be rather inaccurate....

[ChoclateBetta]

Originally Posted by DragonFish

Yes, are there any shells or rocks that you put in there that could possibly affect the PH?
I have Petco sand in various colors in all of my tanks, haven't had any trouble so far....

I noticed you're using the strips.....might want to take a sample of water into your local Petco/LPS and have it tested with a liquid test kit just to double-check before you break down the tank or anything. Strips are known to be rather inaccurate....

You just repeated what I said and rearanged the words.

[Friendlyfishies]

hmmm this may be something to think about??! I had petco black sand in my tanks as well as rocks and my PH was 8.2 which ive heard is quite high...now im wondering if the sand and rocks were causing it?? I tie plants to the rocks but have chosen to go bare bottom lately...im thinking I should check my ph now that I have bare bottoms, no rocks and IAL leaves...maybe its a normal ph now!?

[ChoclateBetta]

IALs help but just 7.5 is a very high PH many african cichlids like 8.2 mine is 7.6 which is hard water but still works if I remember above 8.0 is not good for Bettas and cories.

[Leopardfire]

Maybe you could scoop some of the sand out of the tank, put it in water you know to have a low Ph, and test it after the sand has been in for a while.

Thanks for the tip, I'm doing it right now. Also, there are no rocks or shells that could cause the ph rise. I have tested my tap water ph and it is at 7.5 like the rest of my tanks. I have already lost 2 of my 4 cories and the other 2 are barely alive. They hardly eat and almost never move. My plants are also turning yellow and dying from the ph.

[DragonFish]

Originally Posted by ChoclateBetta

You just repeated what I said and rearanged the words.

Well, I apologize.....aside from agreeing with you about the shells and rocks, that was not my intention nor did I see that thats what I was doing.

Hmm...it really does sound like its the sand then.....thats strange. I wonder why this sand would cause this kind of problem for some and not others? I would assume it would all come from the same place....and I've bought locally and ordered online with no problems....