To raise PH in a tank, would limestone rocks help??

Thank you so much SubRosa. I too would be keeping some of the blackwater loving species but as you say, to each their own and she isn't having it. I really appreciate the information. I haven't worried too much about GH and KH much since I tore apart my reef tanks. I know what my numbers are on my tank and it really rarely fluctuates so it's been quite a good while since I've tested my tanks/water (Think I will tomorrow though. :D). I am very grateful for the reminders/advice. Thanks again.
 
Im actually surprised a City/county water district would allow a PH that low to come out of the tap. Most if not all the water districts ive dealt with boost the PH after treatment as it is beneficial for the water and its travels. Have you thought of calling the water company and asking if that low is normal? could be some issue. Have you ever thought of building a reactor for calcium? Same theory as with a reef tank. But you would be using it to boost the waters calcium carbonate levels. thus raising the PH. If you do it under the stand or something in a sump with crushed coral, It wouldnt be seen and would help.
 
I'm with constevens on this one, and I'm starting to question the accuracy of the tests. Not the user, the kit. Has she been using the same kit for a while? If she's using strips, a good quality PH test kit won't break the bank and should at least double check the 5.0.

If by some chance the tap water is in fact that low in PH (still finding 5.0 hard to believe), there's another simple trick from the reefkeeping side that may help. Simple baking soda. Bake it; yes bake the baking soda at 325 for about 3 hours. Baking it drives out the CO2 in it, and when dosed, will increase PH as well KH. The baked baking soda needs to be dissolved before dosing it. It doesn't take much, and not knowing the tank PH at any given time or the total water volume, she can start with as little as 1/4 teaspoon dissolved in a cup of warm water. I always bake a big box of it on a cookie sheet and just store it in an airtight glass canister. A one pound box goes a LONG way. She can use the same stuff on her new water she uses for changes with a little experimentation to get to a target PH and KH.
 
Im actually surprised a City/county water district would allow a PH that low to come out of the tap. Most if not all the water districts ive dealt with boost the PH after treatment as it is beneficial for the water and its travels. Have you thought of calling the water company and asking if that low is normal?

I also think this is the place to start. Water utilities adjust water pH above 7, in order, to prevent lead, copper and other heavy metals from "going into solution". Kind of leads me to believe, there may be a "piece of the puzzle" missing.
 
Thank you Canuck, bushkill and constevens. I am getting my info from her second hand at this point. I intend to go over this weekend with my liquid tests in hand and test it myself. I know she is using liquid test kits but can not vouch for her accuracy or the exp. date on them. I've questioned it as well because other people I know on that city water supply do not have similar issues.

I like the baked baking soda suggestion. If she is going to put an additive in the water, that would be far more cost effective I would think. I'm not sure how much she spends on what she is using, but baking soda is cheap.
 
Yeah, I guess to take the logic a step further, if water parameters look off the wall the first place to look would be at what's in the tank. As others have suggested, unless what she has in the tank is really fond of blackwater the tank inhabitants might not be looking so hot. If they don't look bad, the test is definitely questionable and should be doublechecked. And lastly, constevens is dead right. At 5.0 coming out of the tap, that water system spend a lot of money replacing pipe.
 
Is there any drift wood or peat in the tank? If so the tannins from those can and will cause the water in the tank to turn acidic.
 
Also make sure the test is done after the sample has been sitting out so dissolved gases (ie. CO2) can escape. Dissolved CO2 as carbonic acid will lower the pH. Generally it's recommended to wait 24 hours.

But as Sub mentioned it would be good to know GH and KH as well.
 
AquariaCentral.com