pH trouble/hard water

[ZakTheRipper]

I have a 20 gallon tank that currently only has two residents: an albino oscar and a common pleco. I use tap water that I of course condition with chems first, and I am guessing it's very hard, because I always get a white crusty buildup on certain parts of the tank's outside (Calcium deposits?). The weird thing is, I consistently have a low pH, that usually hovers around 6.0-6.4, despite my using a 7.0 buffer and pH Up. Every time I raise it, within a day or two it's crept back down. Is there some way to control the pH better? Why would it be so low if I have excess Calcium? I've heard that hard water can make it difficult to control pH, but I still don't see what's making it so low.

 

[rich311k]

What is the PH of your tap water? Leave it set out over night and then test it. those PH chemicals do not work very well and you should avoid them. Steady is better than perfect. Welcome to AA!!!

 

[Fishyfanatic]

Harder water makes it easier to control because of the natural buffering capability. VERY soft water is difficult to control because it doesn't have the buffering ability. I'd definately stop using the chemicals. All it is doing is causing the pH to fluctuate. Do you know the hardness of the wter?

 

[malkore]

Stop using pH up/down products, NOW.
Get a Kh test kit and see what your levels are at. It sounds like you have no buffering capacity in your water.

Also, I hope you're aware that a 20gal is not large enough for an oscar or a pleco, let alone both. They'll quickly outgrow it. An adult oscar needs at least 55gallons, preferably 75gallons for the extra width (front to back). ditto for a common pleco. An oscar will easily hit 12" eventually, the pleco even longer.

 

[ZakTheRipper]

Uh, as I understood, these fish will essentially grow the the size of the tank. My pleco has basically stopped growing at around 5-6 inches. The Oscar's growth has leveled off too. I understand that as big as theyse fish can get, they would need a significantly larger tank that I have, but I've been told many times that fish grow to whatever size will work in a tank, if it's reasonable.

The pleco could actually reach up to 16-18 inches.

And yes, my water has no buffering capacity. My tap water is over 7.6.

 

[ZakTheRipper]

uh, disregard all that bad english

 

[Fishyfanatic]

They will NOT grow to the size of the tank. Their bodies will become deformed from lack of space. It is a common myth that they will only grow to their surroundings. Check out this link ATTN: Age Old Fish Growth Myth Uncovered......

 

[ZakTheRipper]

these fish are a long way from being too big to fit. they have plenty of space to move around, and obviously, if the pleco got to be more than say 8 inches i'd be selling it.

 

[Fishyfanatic]

8 inches is way too big for a pleco in a 20 gal tank. The amount of Nitrates that the Pleco AND Oscar produce is enough to cause you to do water changes every few days. Fish should be able to swim freely in a tank.

 

[ZakTheRipper]

well, from head to tail she's about 6 inches now. is that really so uncomfortably large i should be getting rid of her?

 

[Fishyfanatic]

Yes. Commons do not belong in anything smaller than a 55. Even then you have to be careful with their size.