pH problem? and equipment question

[wharfrat48]

Just tested a sample of my water on a pH meter instead of my home test kit and got a suprise. Since I started my tank, last March, my kit reads 8.15-8.2, the pH meter (actually 2 pH meters) showed just under 8. All other parameters are good (at least my test kits say so) 425 Ca, 4.0 alk, 1.024-1.025 sg. I have been using Oceanic salt (w RO/DI/DI), and Kent 2 part additive for alk and calcium. Should I try to raise the pH with sodium carbonate? Limewater? Any guesses why my pH might be this low?

Now my second question: I have access to alot of lab equip at work besides pH meters (spectrophotometers, fluorescent readers, etc etc). Is there any tests I can perform to calibrate/check my home test kits/hydrometer?

Thanks for your time

Rich

[Randy Holmes-Farley]

I'd first comfirm the pH meter result with grocery store borax:

http://web.archive.org/web/20021015005420/www.animalnetwork.com/fish2/aqfm/2000/feb/bio/default.asp

Short of an ICP, there isn't much lab equipment that is easily used. Conductivity probes are very useful. A dissolved oxygen meter would be interesting.

You can make a salinity standard using sodium chloride (or potassium chloride) and a good balance:


Reef Aquarium Salinity: Homemade Calibration Standards
http://reefkeeping.com/issues/2004-06/rhf/index.htm

[wharfrat48]

I double checked both pH meters with pH 7 and 10 standards. Both were right on. I does seem strange that my pH would only be 8 or so. Could ultra pure water be an issue, I think the water I use has been through RO, 2 DI's, and 2 charcoal cartridges.

Rich

[Randy Holmes-Farley]

The pH could very well be low. It often is due to excess CO2 in the air. However, one or both of the standards might also be off. That's why I recommended the borax.

No, the pure water isn't an issue.

[Randy Holmes-Farley]

These articles describe how to raise pH with limewater or other high pH alkalinity supplements (as necessary to maintain normal alkalinity), and by providing more aeration with fresh air:

Solutions to pH Problems
http://www.advancedaquarist.com/issues/june2002/chem.htm

Indoor CO2 Problems
http://www.advancedaquarist.com/issues/apr2002/short.htm

[wharfrat48]

I will double check the pH meters with borax. If indeed my pH is a little low--would you suggest limewater (saturated soln' topoff I assume), or sodium carbonate (how would this be dosed?), or my Kent's 2 part alk part (alk is already 4meq/l). Not sure if it matters, but the bioload is very low in this "new" tank so far.

Thank You again

[Randy Holmes-Farley]

Limewater would be the best bet, although you may not need a saturated solution.

[crpeck]

Hi Randy and Wharfrat,

I am in EXACTLY the same position (pH from 7.7 - 7.9 occasionally dropping in the 7.6s or making it up to 8) and am so glad to find this post. Alk is 9.6 and Ca is 450. I even use the same salt with RO/DI, Kent A & B and have calibrated my pH meter. Next step is to do the indoor/outdoor test. Although in hot and humid Memphis, I don't think I'm going to have much luck getting the rest of the family to deal with open windows if that ends up being the problem.

We have an older home, the tank is running with a skimmer in the sump, one of the two oscillating power sweeps in the tank pointing up to create surface action, and I have two Ice Cap fans creating air exchange in the canopy hood. I'm soooooo frustrated with this chronic pH thing.

So limewater is the way to go. But doesn't that boost ALK and throw off the balance of the Kent A & B? I already screwed things up once trying to drip the Kent A & B with an IV style doser. One was dripping fractionally slower than the other and over the course of a week threw Ca way high and Alk way low. I just don't trust those drip things.

Will washing soda raise pH without boosting alkalinity? I finally have my Alk and Ca balanced and consistent and hate to mess with that.

The links in the pH article above about meter calibration aren't working for me. Are those articles still available?

Sorry to butt in ... hope you don't mind. I was happy to find someone else with a similar problem. Please let me know if you get your tank fixed and how you do it, Wharfrat and I will do the same.

Thanks Randy.

Cathy

[Randy Holmes-Farley]

But doesn't that boost ALK and throw off the balance of the Kent A & B?

No, because it is also adding a balanced amount of calcium. :)

For that perspective it is a much better choice than washing soda, which will not raise pH as much (although it can raise pH quite a bit), and will boost alkalinity relative to calcium.

Bingman's borax article is only hosted at a web archive site that sometimes is off line. At this moment, it seems to be working. :)

[crpeck]

Thanks, Randy

If it raises both, then I should eliminate or cut back on the Kent A & B? I'm trying really hard to get this straightened out before I leave my husband with my tank for a week while I'm out of town.
I'm afraid .... very afraid :(

I'll start searching on setting up limewater then.

The link still isn't working for me, but I'll keep trying.

Thanks again!
Cathy

[Randy Holmes-Farley]

Maybe. If it is added just to boost pH, you may not be adding all that much in terms of calcium and alkalinity.

Maybe the site is blocked from you somehow, because I just pulled it up again. Don't cut and paste it, just click it.

[crpeck]

I found this article:

http://www.advancedaquarist.com/issues/feb2003/chem.htm

No way can I start this without being here to test water next week and monitor the effect of the change. Think I'm going to have to keep the status quo for one more week and start this when I'm back. My husband can handle adding the Kent (I hope), but starting limewater without testing every day until I see what it does sounds really dangerous to me.

The animals look healthy, except for the starfish that still is freaking out over the IV drip fiasco.

Thanks!
Cathy

[crpeck]

The link definitely doesn't like me. I'll try to get to it another way.

[Randy Holmes-Farley]

You're welcome.

Waiting until you come back sounds like a good idea.

Have a nice trip. :)