Tropical Fish Keeping - Aquarium fish care and resources

Tropical Fish Keeping - Aquarium fish care and resources (
-   Beginner Freshwater Aquarium (
-   -   Brita & lower PH? (

PCT 05-16-2009 12:56 PM

Brita & lower PH?
My tap water has a PH of around 8.0 and a KH of 6 degrees. Since the water that comes out of my Brita filter has a PH of 6.0 and a negligible KH, I've been mixing it about 50/50 with the tap water when I make changes on my freshwater planted aquarium (15 gallons). I've been doing this weekly for about a month, but the PH in my tank keeps getting higher! My KH has dropped to 4 degrees but my PH is around 8.5. What gives? Any thoughts?

Byron 05-17-2009 02:06 PM

Not sure, but a couple of suggestions to consider. First, is there anything in the tank that might raise the pH, namely, rocks or calcium-based gravel? Limestone, dolomite, coral, shells all release minerals into the water over time and have the effect of raising hardness and pH.

Second idea, how does the Brita treat the water (I'm not familiar with these filters)? Does it add anything to the water, or just run it through a filter (but what's in the filter)?

Thirdly, the tap water may be buffering the mixed water and would raise the ph accordingly. But I wouldn't expect it to be above the tap water pH in the end. I'm not very experienced in this area, having always had soft slightly acidic tap water, so others with experience in dealing with harder water may have more help.

aunt kymmie 05-17-2009 02:51 PM

I use a Brita filter too and I thought the only thing they had inside them was carbon to filter out impurities from the tap water. My tap water comes out at 7.8 and is very hard. I just tested the water that comes out of my Brita filter and it tests at 6.0. Maybe even lower, but the card color stops at 6.0.
Carbon alone doesn't change ph, correct??

I don't bother to use the filtered water from my Brita in my tank(s) as I never want to have to fiddle with ph. In order for me to keep a stable ph that means keeping a ph of 7.8.

PS. PCT, Welcome to the forum! What type of fish are you keeping, or planning to keep?

PCT 05-18-2009 09:21 AM

I just took out some rocks I had in there. I'd bought them at the lfs (they were packaged), and I figured they'd be fine in a freshwater system. Don't know why.
I'm trying to lower my PH because my plants are struggling, even though they have good lighting (CoraLife 48 watts on a 15 gallon) and I fertilize weekly (Plant Gro). Right now the staghorn algae is winning the battle. I currently have about two dozen baby platys (their parents were reproducing like rabbits, so much so I finally had to take them back to the lfs) and three rasboras. As the platys grow up I'll bring them to the lfs and only keep a couple.
Problem is (if that's what it is) that the fish are doing much better than the plants, and I'd love to have a beautiful underwater garden, if possible without the hassle of a CO2 system. Any suggestions? And thank you both for your quick replies.

1077 05-18-2009 10:37 AM

Google search for ,"info on product Brita water softener" indicates that those who turn out this product don't recommend it for use with tropical fish.
In any event your platies ,which are livebearer's like mollies and guppies,, prefer hard alkaline water as evidenced by the platy fry they are producing .And these fish do poorly in the long run with soft or acidic water.:cry:

Byron 05-18-2009 01:18 PM

I fully concur with 1077 on the livebearers, they all prefer slightly alkaline (I guess it is now termed "basic"?) water and will not fare well in acidic water, at least that has been my experience.

Given 1077's news on the Brita, I wouldn't use water that goes through one of these. As Aunt Kymmie has confirmed, they do seem to do something to chemically alter the water, as I also agree with her that carbon filtration would not lower the pH from 8 to 6. That's a change of 100 times the acidity/alkalinity of the water.

Re the plants. Yes, some types prefer slightly acidic to neutral pH water, but there are some that would thrive in your water. Vallisneria will grow like weeds, at least it did for me several years ago in a livebearer tank with dolomite to keep the pH in the high 7's and with one 15w fluorescent tube. That was a 15g tank too. You have a fair amount of light (which is why the algae is rampant, they can convert carbon from carbonates better than plants and in such bright light will readily do so) so you might want to reduce the lighting period. Once you get some plants growing, experiment a bit and find the balance. When light and nutrients are in balance, the plants will thrive and algae will not gain a foothold.

CO2 is one way to reduce the pH but myself I wouldn't go down that road until some other things have been tried. The rocks may have been part of the problem if they are calcium-based, so removing them may see the pH fall to the tap water level of 8 or a bit below. Once that occurs, I think you're all set for livebearers, and try some Vallisneria and other plants that are not so fussy about water pH. Some of the swords will do quite well as long as the water is not too alkaline, and with your bright light the stem (bunch) plants should be OK. There are several sites on the web with plant info that you can Google.

PCT 05-19-2009 12:30 AM

Thank you so much, Byron. Very helpful. I will indeed try some Vallisneria, experiment with my light exposure and browse through the Plants postings for more info.

Byron 05-19-2009 09:06 AM


Originally Posted by PCT (Post 196909)
Thank you so much, Byron. Very helpful. I will indeed try some Vallisneria, experiment with my light exposure and browse through the Plants postings for more info.

Co-incidentally, this same topic of plants in harder/alkaline water came up yesterday in another forum I belong to, and someone there suggested Anubias (and Vallisneria again). And there are of course several different species in both genera so some variety. A plant guru on that forum also commented that many plants can do well in water with a pH in the 7's (which is where I think yours will settle out if the tap water is 8; tanks tend to go slightly down in pH as the biological system matures). Anyway, you should have lots to chose from. Keep us posted on developments. Everyone here is eager to see things working well.


All times are GMT -5. The time now is 06:44 AM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

For the best viewing experience please update your browser to Google Chrome