Wicked Low pH

**Stew Jenkins** · 02-09-2008, 12:34 AM

I started a 30G a few weeks ago and im baffled by my pH problem and so im seeking some knowledge.
It's a very basic setup: moonlight sand substrate, 10 small slate slabs, rena smart heater, rena smart filter, 18 inch air cable, 2 small albino corys, 3 paradise, 1 red sword tail.
I tested my initial tap water and it was at pH 7.4. After about 2 weeks of healthy tank activity and normal all around test readings, i noticed my active pH meter looked dangerously low so i tested with a pinpoint digital pH monitor and it was nearly at 4! How could that have happened? I put in a little pH up solution to ward off immediate death but i know thats not a long term solution.
I'm wondering how such a major drop in pH could have occured and how i can stabilize it back at normal levels. Any information would be greatly appreciated!

**smaug** · 02-09-2008, 12:37 AM

I have never heard of such a ph drop.do you have city or well water?

**Stew Jenkins** · 02-09-2008, 12:45 AM

L A city's finest. I have another small quarentine tank with the same water and the same slate, and it's doing perfectly fine. Weird right?

**Dave66** · 02-09-2008, 12:47 AM

Originally Posted by Stew Jenkins

I started a 30G a few weeks ago and im baffled by my pH problem and so im seeking some knowledge.
It's a very basic setup: moonlight sand substrate, 10 small slate slabs, rena smart heater, rena smart filter, 18 inch air cable, 2 small albino corys, 3 paradise, 1 red sword tail.
I tested my initial tap water and it was at pH 7.4. After about 2 weeks of healthy tank activity and normal all around test readings, i noticed my active pH meter looked dangerously low so i tested with a pinpoint digital pH monitor and it was nearly at 4! How could that have happened? I put in a little pH up solution to ward off immediate death but i know thats not a long term solution.
I'm wondering how such a major drop in pH could have occured and how i can stabilize it back at normal levels. Any information would be greatly appreciated!

Was the Pinpoint pH monitor properly calibrated? If so, which solution did the owner use to calibrate it? There are 5.0, 7.0 and 8.0 calibration packets. If he calibrated it at 8.0 it wouldn't read your lower pH accurately.
Your pH is dropping like a stone like that because there's not enough carbonate hardness to keep the pH stable. I take it your tap water is very soft? There are products designed to reconstitute reverse osmosis water to make it suitable for fish by adding electrolytes and minerals. A steady pH can be achieved by adding the products to your tap water, hardening it just enough to buffer your pH. Carbonate hardness in sufficient amounts resist pH changes.
Just FYI, my tanks are pH 6.8, gH 4 to 5, kH 5 to 6 and dead stable. I mix RO/DI water 70-30 with my rock hard tap water to get those readings.

Dave

**Stew Jenkins** · 02-09-2008, 12:59 AM

Way cool Dave i appreciate that.
My readings are as such after putting in pH up: gh 12-13, kh 3-4, pH 4.31
I'm no scientist but it just seems all outta wack to me.
I have a quarentine tank with the all the same water and goods in it and all readings are dead normal. Maybe i just have an angry neighbor who hates me and corys and is trying to sandbag my tank by sticking chemicals in it when im at the store or something.

**Dave66** · 02-09-2008, 01:17 AM

Originally Posted by Stew Jenkins

Way cool Dave i appreciate that.
My readings are as such after putting in pH up: gh 12-13, kh 3-4, pH 4.31
I'm no scientist but it just seems all outta wack to me.
I have a quarentine tank with the all the same water and goods in it and all readings are dead normal. Maybe i just have an angry neighbor who hates me and corys and is trying to sandbag my tank by sticking chemicals in it when im at the store or something.

I take it the decorations are different between your quarantine and main tanks? What kind of decorations are in the main tank? Something is sucking the life out of your pH by depleting the carbonate hardness. What all chemical additives do you/have you added to the tank. Do you have any kind of resin-based media in your filter?
All things being equal, there's something in the main tank that's different from the quarantine. Take some work to figure out what.
Ah, occurred to me, do you run an air stone in that tank? Makes me wonder if there's too much Co2 in the water. If you run an air stone, it'll out gas the Co2 and the pH would rise.
You have quite a puzzle, but we here can probably solve it.

Dave

**smaug** · 02-09-2008, 03:04 AM

Originally Posted by Stew Jenkins

Way cool Dave i appreciate that.
My readings are as such after putting in pH up: gh 12-13, kh 3-4, pH 4.31
I'm no scientist but it just seems all outta wack to me.
I have a quarentine tank with the all the same water and goods in it and all readings are dead normal. Maybe i just have an angry neighbor who hates me and corys and is trying to sandbag my tank by sticking chemicals in it when im at the store or something.

your gh and kh readings are almost identicle to mine,I do not believe it has anything to do with those.Do you have test equipmet for anything else ,such as phosphates?