On Sun, 26 Mar 2006 08:06:20 GMT, "ML" wrote:

I have a 20g fresh water tank that is 3+ years old.
Our water is naturally soft and I have problems keeping the PH up. It is a
community tank and I would like to keep the PH around 7.0. It is currently
about 6.6.
I have done frequent water changes and I use a gravel filter to drain the
water.
The Nitrates are about 20 ppm.
I have a penguin bio filter which I change monthly and an Ehiem canister
filter left over from my 55g tank from years ago. The Ehiem filter I clean
about every 3 months. I cleaned it about 6 weeks ago.
Right now the tank is very clean.

3 weeks ago I added 4 fish and lost 3 of them plus 5 other fish.
I took my water into a fish store to be checked.
The PH is low which I know and so is the alkalinity.
A couple of years ago when I had PH problems before, I got advice to add
crushed coral and maybe some sea shells as a natural way to raise the PH.
This seemed to work for about a year. I recently added a few extra sea
shells to try to raise the PH.

Is there a natural way to raise the alkalinity? I am guessing that is part
of the reason why my PH is so low. The fish store folks are trying to sell
me some buffering chemicals which I want to resist if I can.

Thanks,
Mark

For openers, a pH of 6.6 and soft water sounds fine for most community
fish, unless you intend to breed certain fish, and even then you may
be OK with most. In fact, it's exactly where all of my tanks settle by
the time they are due for their next weekly water change. Out of the
tap, my water is pH 7.0 and very soft. I have never really mastered
the fine points of hardness and alkalinity, and most of the time
knowing the difference between soft, medium and hard and buffering
capacity is enough to get me through. When I've let a tank really go,
like no water change for 6 months, my pH will drop to 6.0. The fish
were less upset than me. What is your procedure for acclimating and
introducing new fish to your tank? My tanks contain Angels, guppies
livebearers, tetras, corys, barbs, which are commonly considered
"community tank" fish. What is your pH and hardness straight from your
tap? It sounds like you are depending on your pet store to test your
water, you need to buy a test kit so you can check the basics, pH,
Ammonia, Nitrites, Nitrates and a hardness kit would be nice too. I've
read from several people here that "the pet shop tested my water and
said it was fine" - - if you have your pet shop test your water again,
ask them to write down for you exactly what they tested for and the
numbers. Ask them to do each of the tests I mentioned above, if
they're nice guys they'll do it. Money spent on a test kit would be a
better investment than more fish at this time. API's Master Test Kit
is good enough for most purposes and It costs around 20 bucks. It does
not include a hardness test. You can call your water company for that
information, or you can get the exact numbers from your pet store.
"Very soft" is good enough to know at this point. You haven't told us
how many and what kind of fish you have in the tank and what kind of
fish you just brought home and lost. Do you have live plants? How
often do you do water changes and how much water do you change at a
time? Yes, crushed coral is a good, "natural" method to increase your
buffering capacity. I've used it many time before to raise the pH and
buffer for some livebearers I was breeding. I place about half a cup
in a mesh bag and add it to a chamber in my HOB filter. I strongly
encourage you to stay away from chemical pH changers. They can be
tricky to use and even trickier to maintain the target pH. And your
tank volume isn't large enough to be very forgiving for any mistakes.

I just read what I've written above, dotting my "t's" and crossing my
"i's" - it reads like I'm lecturing you - believe me, I'm not. Getting
the answers to the questions I've asked will help us help you a lot
more effectively.

-- Mister Gardener