pH and Fish Only Setups

[Morgman]

Randy,

First off, thanks in advanced for any feedback and time spent on this question. I posted this in your forum because I believe you are the most knowledgable on this topic. Thank You.

Here is my dilemma; I have some very dense populated clownfish breeding (brood) tanks and growout tanks that have been having problems with low pH. And low I mean high sevens. Before I did a water change on the brood setup I had readings of

I am not sure exactly because I am using Salifert's pH test. No matter what I know the pH is too low. I am planning on getting a digital pH probe so I have a better understanding of how much this pH needs adjusting.

These tanks get feed tons of food and the major cause of pH drop is due to organics. Each system is in the 300 gallon range. Even after a large water change of 95 percent of the system I am still at 8.0 after a few days. I did the CO2 test with no change in pH.

I have been contemplating on a better route to stabilize these pH swings over a period of time. Since I add RO water via a float switch I figured the use of a 2 part system or maybe a kalk additive will help. What do you think would be the best bet on pH stabilization? I am leaning towards your 2 part additive. The amount of calcium is not really the factor here it’s the stability and buffering capacity of the water (Alk) for these fish.

Now that I write this I realize I need Alk and Ca tests. I will pick these up tomorrow and see what I am running. I am mostly concerned because I did some larger water changes and still I am seeing low pH.

Here is a quick run down of one of my tanks,

Sg 1.015 or 21 ppt
NH4—0ppm
NO2—0-.1ppm
NO3—25 ppm
pH 7.7

[rsman]

I use kalk in a DIY nelison style reactor, setup to go on when the waterlevel AND pH is low, and a venturi pump in a sump not hooked up to anything just stirring up a foamy area in the sump (rubbermade ), both work good, I have in the past used O2 with a pH probe, but have kinda let that go everything seems to work just fine w/o it. also over filter, you cant have too much filtration. additionally CO2/O2/pH are some of the reasons I like bio-wheel like filters better than most of the trickle style filters.

[Randy Holmes-Farley]

I am not sure exactly because I am using Salifert's pH test. No matter what I know the pH is too low. I am planning on getting a digital pH probe so I have a better understanding of how much this pH needs adjusting.


The Salifert pH kit sometimes reads low when old, but your pH may really be low as well.

I did the CO2 test with no change in pH.


You aerated with indoor or outdoor air, or both?

The pH should rise outside unless the alkalinity is low. What is the alkalinity? If you have normal to high alkalinity, and the pH is below 8 after aerating a lot with outside air, then there must be a measurement error of some sort (alkalinity or pH).

When you say pH stabilization, do you mean just raise the pH, or do you see a big daily pH swing as well?

Limewaer and the two part additives would be a good choice, IMO.

[Morgman]

Rsman---

Thanks again for all your input. You are always helpful.

Randy,

I need to raise the pH and keep it constant between water changes. I am not worried about daily swings. I still haven't had a chance to get an Alk and Ca test. The place I was counting on having thgm didn't have them. So I will have my Ca and Alk radings soon.

I did the aeration test in the same area as the tanks. So I will move it outside and check the results.

Do you think using the 2 part solutions will be more forgiving at balancing out this problem. I am thinking off Murphy's law here and I figure one day or another I may accidently dose a 5 gallon of kalk in this system and I woud hate to shock all of my fish. So with this in mind I assume the 2 part keeps the Alk more consitent than kalk and as a result keeps the pH rather stable over a given week.

Thanks again for your time and opinions.

[Randy Holmes-Farley]

Do you think using the 2 part solutions will be more forgiving at balancing out this problem.

Than limewater? No. It has a lower pH raising effect per amount of calcium and alkalinity added, and in this system, you don't have much demand. So I'd use limewater.

OTOH, if you might accidently dose 5 gallons of limewater, that is a concern.

[Bomber]

Morgman

If I may.

For one thing, fish are not that concerned with pH and somewhere in the 7's is fine with them. Rapid changes "are" a concern. Be careful relying on anything that you add or hook up that could do that.

That said, just raise your alk that will buffer your ph and Arm and Hammer is perfect for that.

Also, as you know, suppression of pH is from dirt. Try to keep the systems as clean as you can.

[Bomber]

Also try not to use any form of biological filtration that traps dirt and allows it to sit and rot.

[rsman]

Thanks again for all your input. You are always helpful.
I generally try to be, usually i just end up confusing people
Also try not to use any form of biological filtration that traps dirt and allows it to sit and rot.
what he said

the problem here is this isnt just a FO, if you dont control this a LITTLE, itll get worse. and IME when it does it gets worse fast.

because of the extremely high bio-load of a grow out tank, you get a consumption of alk, plus the consumption of lots of O2, which is replaced with CO2 and both lower pH. and though the 7's are ok the 6's and 5's are NOT.
if that makes sence