# Can't seem to lower pH



## DJKronik57 (Apr 17, 2006)

I've got a 20 long that seems to have a pH of around 7.8 and I can't get it to drop using DIY CO2. The water from the tap has a pH of around 9, but it usually drops down to around 7 within 24 hours (even without CO2). My other tanks stabilize with CO2 around 6.8. This tank had dropped to 7.2, but now its back up to 7.8, even though I haven't changed anything! My KH is between 6 and 7 and the GH is 75ppm. How can I lower the pH safely without pressurized CO2? Should I add another CO2 bottle?


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## niko (Jan 28, 2004)

I'd first look for better ways to disolve the CO2.

If you have a diffuser don't just let the bubbles go up to the surface. Put the diffuser under a small powerhead. The efficiency of the CO2 solubilization is increased at least 50% if not 75%.

If you don't have a diffuser just wedge the end of the CO2 tubing in the intake of the powerhead. Compared to the diffuser/powerhead combo you will see bigger bubbles coming out of the powerhead.

That is the simplest way to disolve CO2 and if you like it it's very efficient.

--Nikolay


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## DJKronik57 (Apr 17, 2006)

That's what I've been doing. I have a Hagen CO2 canister with the output tube right into my powerhead, which feeds right into my home-made canister filter. The bubbles get chopped into tiny ones, and that happens quite frequently (every other second or so). Still not enough to lower the pH.


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## niko (Jan 28, 2004)

In that case how much surface agitation do you have?

--Nikolay


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## DJKronik57 (Apr 17, 2006)

The output of my canister filter is near the surface, just under it but the flow of water is not breaking the surface, just causing a few small ripples. Should I aim it further down so it doesn't move the surface at all? Re-tested pH this morning before lights on and it was 7.4-7.6.


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## DJKronik57 (Apr 17, 2006)

Is it hopeless to use something like Seachem's Acid Buffer or Liquid Acid Regulator to lower the pH? Will this just stress out my fish? From Seachem's website:

_
Liquid Acid Regulator™ adjusts pH to the acidic range (4.5 - 6.8 ) and softens water by precipitating calcium and magnesium. Liquid Acid Regulator™ supports the establishment of the optimal environment for all acid acclimated species (e.g. neons and other tetras, etc.). For further freshwater environment enhancement, use Fresh Trace™ to restore the proper level of trace elements required by thriving, healthy freshwater community fish.

Acid Buffer™ is a non-phosphate buffer to lower pH and buffer with Alkaline Buffer™. Both buffers are designed for the planted aquarium or for very hard water where phosphate buffers may pose an algae or cloudiness problem. Acid Buffer™ lowers pH and buffers between 5.0 and 8.0 when used with Alkaline Buffer™. As Acid Buffer™ lowers pH it converts carbonate alkalinity (KH) into available CO2. It may also be used to safely lower pH in marine water._


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## Chris S (Feb 27, 2006)

If there are micro bubbles coming out of your canister outlet I would say lower it or aim it dwwonward to keep those bubbles in the tank as long as possible.


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## erijnal (Apr 5, 2006)

If your plants are doing well, I'd just not try to screw around with the pH as long as the livestock is happy. Remember for planted tanks your ultimate goal is to get CO2 into the water, not lower the pH. A lower pH is simply one of the usual signs that your CO2 is being dissolved efficiently, but the change from CO2 to the carbonate ion may be impeded by the carbonate hardness. Your kH is actually sort of high so if you want to get the pH down a lot, you're going to end up having to dissolve a LOT of CO2, which could cause respiration problems for livestock.

If you do want to try to go to a lower pH though, scrapping the Hagen canister and going with either one or two 2L bottles sounds like a good plan.

Some of the specifics are probably wrong, but the general idea should help you out.


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## DJKronik57 (Apr 17, 2006)

Thanks for the advice erijnal. I will try adding another CO2 bottle. Problem is I'm keeping Rummynose Tetras in the tank and they don't look very happy (they are only slightly red, compared to the old tank in which I used peat to make the water more acidic--their noses were BRIGHT red). It's an iwagumi style tank so using peat is not preferred as I don't want brown water. So what about those Seachem chemicals? Is it safe to use them?


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## hoppycalif (Apr 7, 2005)

Wait!!! Don't touch the chemicals yet! I suspect you might do well with softer water, but pH is not going to be a solution to anything. So, why not try to mix in some RO water to lower the hardness? Fish don't require a certain pH range, except a very broad one, but some do prefer softer or harder water. Adding unneeded chemicals just leads to adding more until you have a chemical soup you can't even maintain the stability of.


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## DJKronik57 (Apr 17, 2006)

Okay, but the Liquid Acid Regulator just precipitates the calcium and magnesium out of the water...which would make it softer, thus reaching the same goal as adding RO water (which I don't have). Or does the calcium and magnesium precipitate get re-absorbed into the water after a certain period of time? What exactly happens to the calcium and magnesium?


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## Salt (Apr 5, 2005)

Seachem's _regulator_ products are phosphate based. (I don't know the exact chemicals.) Acid regulator lowers the pH using a type of phosphoric acid. It may lower calcium and magnesium, but it's also adding other chemicals that end up replacing the calcium and magnesium which precipitate out, thus increasing TDS (total dissolved solids). It will also invalidate the KH/pH/CO2 chart because that chart assumes no other acids or bases in the tank besides CO2 and CO3.

Seachem Acid Buffer is mostly Sodium Bisulfate. This reacts with the carbonates in the water (CO3) and turns it into CO2. The net result is you lower your KH. (But keep in mind it adds sulfates, so it _increases_ TDS.) Of course the CO2 from this reaction doesn't last very long. However, it _will lower_ pH by lowering the KH. It also doesn't invalidate the KH/pH/CO2 chart.

Seachem Alkaline Buffer is for the most part baking soda. (A tech once said it's more refined than food grade baking soda, plus it has some smaller quantities of other bicarbonate compounds as well.) It raises KH, pure and simple.

In your case, since you are unable or unwilling to go to pressurized, I would probably try adding another CO2 bottle before doing anything else.



hoppycalif said:


> Fish don't require a certain pH range, except a very broad one


In my personal opinion, that's misleading advice. There _are fish_ that won't fare well in water chemistry that has a pH which is too high or low. For example, would you advise keeping discus in water with a pH greater than 8?


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## hoppycalif (Apr 7, 2005)

Salt said:


> In my personal opinion, that's misleading advice. There _are fish_ that won't fare well in water chemistry that has a pH which is too high or low. For example, would you advise keeping discus in water with a pH greater than 8?


A ph of 8 would be way outside of a "broad range of pH". A "broad range of pH" would be more like 5.5 to 7.0. The TDS involved to get to a pH of 8 would probably be outside of the range that discus could tolerate. But, I believe it is that high TDS and not the pH, which is a consequence of the high TDS, which makes that not acceptable for discus. If, for example, one were to add acids to a tank with pH8 water, they could lower the pH to a "reasonable" 6.5, but the TDS would be even higher and the water even less suitable for discus. That's how I understand it.


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## DJKronik57 (Apr 17, 2006)

So, I've read somewhere on this board (can't remember where) that having an bloom of algae can cause your pH to increase. Is this true, and if so, why? I'm currently battling a Green Water outbreak (my first) and the pH will not budge from 7.8, even after adding another CO2 bottle. KH is 100-120ppm, GH is 75ppm.

My other question is, what about water softner pillows/pads? If I put one in my filter, it will lower GH, but will this help stabilize the pH at a lower level or just add to my problems?

*sigh* If only I could afford pressurized CO2... :wof:


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## MatPat (Mar 22, 2004)

Do not mess with the water softener pillow. They remove the "hardness" (GH) from the water but do so with sodium. It is the same theory as using a water softener in your house to remove the magnesium and calcium hardness. The TDS in your tank may rise even though the GH may lower. This will probably do nothing for lowering your pH and may increase the sodium content of your water, terefor increasing the TDS.

In regards to lowering the pH you will need to either lower your KH or get more CO2 into the tank. The best (safest) way to lower your KH is with RO water as you hve probably already read about in this thread

Depending on where you live you may not need to purchase an RO unit or store a lot of water. In my area,nearly every grocery store sells either RO or Distilled Water. Wal Mart may be a good place for you to check. Some of the better LFS even sell RO water. With a 20g tank, you would only need 10g of Ro for your weekly water changes. Last time I paid attention to the cost of RO/distilled water at Wal Mart is was under $1 per gallon.

I would definately look into trying to get the CO2 into the tank a littl more efiiciently. In my opinion, if you are seeing bubles come out of your filter, you are not getting a very good diffusion rate or simply putting too much CO2 into the filter. Since you cannot get the pH to drop, it is doubtful that you are putting too much CO2 into the filter.

For a cheap diffusion solution, look into getting some Sweetwater Fine Pore Diffusors from Aquatic Eco Systems These diffusors (air stones) work very well and I have found that I need to actually decrease the the CO2 output in my pressurized system when using them. These stones do require a higher pressure than the  Sweetwater Medium pore diffusors and may not work with a DIY system. Since you are not using pressurized, you may want to order one of each and see how they work.

These will definately help you get more CO2 into your tanks which may be all you need. I run one stone under a Rio 180 powerhead in a 50g tank. The bubbles are so small going into the inlet of the Rio that you don't hear it "chopping" them up. Also no "visible" bubbles come out of the output of the Rio so I would have to say it is pretty efficient. The downside is they will need cleaned (I soak in bleach for an hour or two then usually let them sit in H2O2 overnight) every week to 10 days but it is easy to do with the regular weekly water change. Hmm, you may want to order two of each so you can clean one while the other is in the tank


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## DJKronik57 (Apr 17, 2006)

Hmm, your RO water idea sounds promising, I know my local pet store sells RO water for salt water tanks. How do I find the right mix of RO and tap water without experimenting in the tank? My tap water has a KH of 30ppm and a GH of 25ppm (very soft water!). Yet all my tanks have a KH and GH that is substantially higher. What's up with that?


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