Stubborn water

[woodlitnight]

I have a water problem that has been perplexing me for a while now.
6 months ago I set up my very first fish tank. Its your standard 29 gallon, nothing fancy.
The water from my tap is 7.6pH, 20dGH, 6dKH. I didn't really worry about any of that (being a newbie and whatnot)
until one month into my tank I decided I wanted to go the planted route. My ultimate goal is to get my water
around 7.0 pH and whatever GH/KH required to support it there.

Since then I've been in partial water change hell just to get my numbers where they need to be.

To condition the water, I use Aq. Pharm's "Stress Coat".

Month 2, I first tried using Aq. Pharm's "pH Down"... no dice. I'd add it until i got the pH down to 7.4
then bang, 24 hours later its back up at 7.6. Did this about 8 times before giving up.

A little later I discover KH & GH and realize how crazy high my GH was. I found a nice water source
providing pH6.0, 0 KH & GH... nice and happily on the other side of the spectrum from my water.

Month 3 I began my every other week 10 gallon water change routine using the water described above.
Again, pH drops but within 24 hours its back up.

Month 4, I purchase a Hagen CO2 diffuser and patiently wait to see some change..
I did see a one stop drop from 7.6 to 7.4, but nothing further.

Month 5 I begin removing the misc rocks prior to both water changes in attempt to asertain if any of them
are causing my problem. Again no dice. pH rises back up to 7.4 after 24 hours

Month 6 is here and I still have the same pH problem. In fact I just did a 10 gallon change yesterday.
Pre-change stats were pH 7.4, KH 5, GH 9...
Post-change stats were: pH 7.2, KH 3, GH 7...
24hours later: pH 7.4, KH 3, GH 7

What am I missing here? I've been able to drop my KH & GH no problem, but pH remains a thorn in my side.

Thanks, and Happy Thanksgiving!

 

[Fishboy-from-NY]

you dont have to do water changes all the time, I wouls just treat the whole system until you get it to the correct PH, then test it periodically until it stabilizes at the desirable level.

 

[jsoong]

Chasing pH with pH altering chemicals is a waste of time, not to mention dangerous to your fish! All you end up doing is creating pH swings & exhausting your buffers. pH swings are bad for fish. It would be far better to adapt your fish to the new pH, rather than constantly messing with the water. If you have really sensitive fish or if you ar breeding fish & need a specific pH rather than one you have, then you'll need to look at another source of water, such as RO.

Yout KH is good, it means you have good buffering capacity, and it should keep your pH nice & stable. The flip side is that, it will be difficult to alter the pH with pH down, etc. as you have noticed.

Adding CO2 will lower your pH. If you look here at the KH/pH/CO2 table:
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm
you'll find that at your KH of 6, you need to add CO2 till you have around 20 ppm to reach pH of 7.0. This gives you perfect CO2 levels & just the pH you wanted.

BTW - the pH/KH/CO2 calculator will not work right if there are other buffers - such as your pH down, & you need to get that out of your system for proper result. (read the info with the table, gives you a good grounding on CO2, etc)

You problem, therefore, is not enough CO2 outpu tfrom your system. I have not use CO2 so I cannot provide advice. Check the planted tank forum, there's tons of info on CO2.

 

[Allivymar]

Hiya Cratch n welcome to Aquariumadvice

Oooo...a mystery. If I read your post correctly, you're using water with a 6.0 pH for all your water changes (or are you mixing the RO/DI water with tap?). I also would think the pH would be lower if thats the only water being used, which leads me to believe its something in the tank thats kicking it up. You've checked the rocks, what about the substrate? What are you using?

And just to be thorough, what else is in the tank? What sort of fish, decor, filter, media, etc? What are the other water parameters?

Also, just a thought, but when did you check the pH on the RO/DI water? Right after it was poured? Or 24 hours later? While it shouldn't change after a period of time, unlike some tap water, maybe theres something going on with the source? What is the source btw?

 

[woodlitnight]

Okay, here we go.

Substrate:
no laterite yet, just std gravel you buy at the pet store.

Tank Contents:
4 tiger barbs,
2 algea eaters,
6 blue lookin' tetras, not painted
4 more tetras, I think they're silver tips
2 pearl gourami
3 red dwarf gourami
1 spiney eel
3 cory cats
2 sword plants
a couple bunches of long grass
2 clusters of bunch plant
2 pet-store purchased slate rocks
1 thermometer
1 hagen CO2 thingy
1 heater
No guady plastic crap in tank.

Products used in the tank:
Stress Coat at water change
10ml FloraPride once a month at water change

Added Water Source:
Bottled water I purchase at the Clemen's in Lionville.
74 cent gallons of "Pocono Spring" water out of Mt. Pocono, PA.
Its consistenly been 6.0 pH, 0 GH, 0 KH each time pre-addition to tank.
I do not mix the water with any of my tap water... or haven't yet anyway.
water changes are ~10 gallons.

I test pH, GH, KH, Nitrate, & Ammonia once a week and have kept written records since October.

I also test pH, GH, & KH twice after a water change
once right after the change
the second time 24 hours later.

Its been pretty frustrating, though the problem keeps me very involved with the tank.

I've also considered using peat in my filter... any thoughts there?

Thanks again!

 

[Allivymar]

I suspect a couple of things here, although I certainly can be wrong LOL

The Pocono Spring water. Do me a favor. Next time you buy some (or if you have a gallon at home) pour some out into a clean inert container and leave it for 24 hours (don't cover it). Test the pH again.

Have you used more then one pH test? I wonder if the test is somehow defective? Prob not, but is a thought.

Test the gravel like you tested the slate. Again, thats prob not it, but at least that can be checked off.

Maybe its the FloraPride? I sorta doubt it, but I came across this rather old post from a diff forum: http://fins.actwin.com/aquatic-plants/month.9602/msg00219.html . Maybe trying a diff fert might make a diff?

Peat will most likely lower your pH, but I suggest we find out WHY its going up. Best to solve the problem then to cover it up.

Btw, you don't need a perfect 7.0 pH to have a well planted tank; you may be driving yourself nuts for nothing *grin*

Lastly, major thumbs up for such great water husbandry! You need it LOL thats some overstocked tank there *grin*

 

[woodlitnight]

Cool. Thanks!

I will try opening the water and letting it sit a day before testing pH.
I've wondered about the Florapride. I think I'll try the same type of test with it.

 

[Allivymar]

Ack; I'm a dork LOL I forgot to mention to aerate the water as well as leave it out. The Ph change can be due to offgassing or ongassing of CO2.

Also, your CO2 levels are extremely low as jsoong said. You want around 15-20 mg/l and you currently have 3.6 mg/l. Its actually a good thing your tank doesn't stay at 6.0 pH tho; at that level your CO2 would be 90 mg/L and would likely kill the fish!

If you want to see the math yourself, check out this site and the calculator at the bottom: http://www.caloriesperhour.com/fish/notes_co2.html

 

[AJ]

I understand your frustration. My pH, KH & GH are all high in my tank. It doesn't matter how much RO water I add, the KH & GH will lower (I had them almost nill at one point - before I had fish in the tank) but the pH remained the same.

Eventually.....I gave up. It really doesn't bother the fish. I don't see anything wrong with your parameters (mine are higher than yours normally with no adverse effects). Stability is the most important thing, not numbers.

So now the fish are happy AND I am happy because the stress of trying to change pH is a nightmare.

 

[woodlitnight]

I'm basing my pH decision primarily on what I've read plants prefer... which is something closer to 7 or so? Thanks for the advice. I'll do what Charlie Papzian suggests... "Relax. Don't worry. Have a homebrew."

 

[vega]

Its better to stick with whatever pH u within now (6.8-7.8) then kept manipulating it. Most fish n plant will be ok within these pH range and the pH swing will do more harm to the fish not mentioning the extra bucks that wasted on this pH issue.