Buffering Capacity - Should I be concerned

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superstein61

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Dec 10, 2002
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Ok, been measuring my PH, Buffering capacity and total hardness on my 72 gallon new setup and my readings are typically:

PH around 6.8
Buffering Capacity around 0
Total Hardness about 120

Should I be concerned with the low to nothing Buffering Capacity - and if so, what are some of the better ways to rectify it?

I am happy with my total hardness and PH levels as they are. Its a community tank - with dwarf cichlids, clown loaches, gourami's, paradise fish and some tetras. All of these will do well in the 6.5 to 7.0 ph range.

I never had a problem on my smaller tank - BUT it was a different mix of fish - and my ph was a bit higher (I think this tank is lower due to the driftwood - plus I used to add some salt to the smaller tank) - and quite honestly, I never worried about the ph and buffering capacity a whole lot.

With this new tank and different fish, I would like to maintain a PH in the 6.7 to 6.8 range -

Thanks
 
When you say buffering capacity ,are you refering to KH? and by total hardness GH? If so you are in troube, I have never head of 0 °dKH. Post what kit you are using and maybe we can come up with somethig. There are many ways to eadsily raise KH to from 4to8°dKH
 
If your tests are accurate and u have no buffering capacity, heck yea I'd be worried. You'll have nothing to guard against acidification and if your not paying attention, your pH could drop very low very quickly.

First off, check your tap water or whatever you use for tank, make sure it is not the reason you have no buffers. If it is very low or non-existant to begin with, I'd find a new source of water.

If your source water is good, then you have something depleting it in your tank WAY too fast and you should make sure your are not overstocked, overfeeding, or have lots of decaying organics in there (clean out filters, substrate, etc...).

For now, I'd add maybe 1 tspn. of baking soda (dissolve in some tank water first) and check the buffers after an hour or so. If it's still low, add another dose and check again. Don't be too tempted to add too much too soon, as it has a tendency to have a delayed effect and before you're ready both the KH and pH will shoot up rather quickly. Of course this is just my experience after a few times using it, someone else who has done more than I might have a better procedure.
 
Perhaps your testing technique is too informal. Or you're using reverse-osmosis water and you added Epsom salt to it.

The salt you used to add to the other tank couldn't have been just common sdalt, NaCl, which affects neither the alkalinity ("buffering") nor the pH value or stability.

Are you secretly adding carbon dioxide? What's the missing piece you're not telling?
 
OK, thanks for the replies< I kind of thought that was the case - here is some additional info:

1. I am using Mardel Aqualab I freshwater test strips. I just recently started using these so I am not real familiar with them( I used something different to test in the past). The test strips measure PH, Alkalinity/Buffering Capacity and Total Hardness (yes, while the package, etc doesn't say so - I believe for shorthand purposes you could call the last 2 tests tests of KH and GH - however the testing scale they use seems to be different than most others). The test scale they use for KH is 6 color blocks - 0 or 80 (which they suggest using Buffer up), 120 or 180 (which they identify as ideal range) or 240 or 300 (which they suggest using ph minus).

http://www.mardel-labs.com/mardel/f_atstrip.html

an excerpt from their site says:

AquaLab 1 Test Strips - pH * Buffering Capacity * Total Hardness:
pH, buffering capacity and total hardness are three important properties of aquarium water. PH indicates if water is acidic or basic. Maintaining a stable pH is critical to a healthy aquarium. Buffering Capacity (total alkalinity) stabilizes the pH. Total hardness is principally a measure of calcium and magnesium in the water and is important in maintaining fish health. Simply dip the test strip in tank water and read the results. Test results in only 30 seconds.


2. My 72 gallon is newly set-up. I just finished a fishless cycle of about a month on Thursday. Thursday evening, I did a 90% water change. I added 14 fish on Friday evening and 6 on Saturday (about 22 inches of fish in total - which is a low load considering I had been fishless cycling the last 2 weeks at 3ppm Ammonia which was being consumed in about 12 hours). All the fish seem to be doing well. I have tested for Ammonia and Nitrites often with no problem - and Nitrates have been in the 20 to 30 ppm range.

3. When I did the water change on Thursday, I also vacummed the substrate lightly - so there should not be any significant decaying organics.

4. The tank is planted but not heavily - 4 java ferns, 1 bolbitis fern, 2 larger anubias nana, 1 Anubias Coffeeolia, about 10 small water sprite and 3 large bunches of Anachris.

5. No CO2 injection, no Epsom Salts, no RO water, etc. Just plain tap water - with a standard dechlorinator used.

6. After finishing the fishless cycle, I did add about 75 ML of freshly bought Seachem Purigen in my wet/dry filter sump - and I do have a UV sterilizer running (this is different from the smaller tank where I have used carbon instead of purigen and no UV)

7. The salt added in the past to the smaller tank is just basic aquarium salt (which I have now decided to not use in the new tank after further reading, etc)

Now - Those test readings I posted have been constant for the last few days. HOWEVER, I just retested both tanks right now and my readings are:

Total Hardness - 120
Alkalinity / Buffering Capacity - 80
PH - 6.8 or 6.9

Both tanks are reading virtually the same now. Is it possible the large water change, the dechlorinator or stocking the tank (even though I had been doing a fishless cycle) initially affected the KH knocking it to zero - but now it has risen back to its typical level?

Is 80 kh something you would live if it holds there - or should I try and increase it a bit? With the baking soda - or possibly some Seachem Discus Buffer (which I have on hand basically to use when I will need to recharge the Purigen).

Thanks
 
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Even after your water change, you still have very low KH and your water will be quite susceptible to pH swings. It's possible that your buffering is getting used up and then is replenished when you do a water change.

In any case, finding some way to stabilize KH and boost it a bit, without affecting pH, should be a priority. I'd recommend putting a small amount of crushed coral (a tablespoon or two, for starters) in a filter bag or nylon stocking and throw it in your sump. You should then test KH and pH every several days to see the coral is working. If either KH/pH climb too high, remove a bit of the coral; if they don't climb enough after a week or 10 days, add a bit more. Your goal is to have just enough so that any buffer consumed by natural acidification in the tank is replaced by dissolving coral.

Another thought: I've also used the Mardel strips you mention, and I like them a lot for their simplicity. It's very important, though, that you note the expiration date on the bottom of the bottle. I have found that the accuracy of the strips degrades quite rapidly as they reach that date.

Good luck,
Jim
 
Jim

Thanks for the info - I will give the crushed coral a try as soon as I find some. I assume my LFS should have some - however, is their some product in particular I should look for. With only a few teaspoons needed - it doesn't make sense to buy a bag the Saltwater folks use as a substrate.

Thanks
 
Hey Superstein,
I just got the smallest bag of crushed coral I could find at the lfs. In my case that's a 10 lb. bag. Since I'm only using 5 tblspns (in a filter bag) in my 30g it may just be a lifetime supply, but it was only a few bucks. Aragonite should also work, but I'm not sure about the dose.

If you're alkalinity (KH) is about 80 (assuming thats ppm) you'd have a buffering capacity of about 4.5 degrees. That's not especially low. I naturally have a KH <1 and use the coral to boost it up to about 3 degrees. I'd try to confirm the numbers before I did anything to the water.
 
Crushed coral substrate should be available by the weight from an open bag in your lfs. I have a peanut butter jarful.

Like carpguy, I think you should retest your alkalinity (KH) using a first-rate test and compare to your dry strips before coming to any conclusions.
 
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