Water Chemistry GH KH

So I finally got a GH & KH test kit for my tanks. And I'm a bit shocked by the results of the tests.

Tap Water:

PH 6.5 GH: 25PPM (Very Soft) KH: 0 PPM (No Buffering)

Tank 1: Discus

Temp: 82 PH 6.2 Nitrite: 0PPM Ammonia: 0PPM GH: 75PPM (Soft) KH: 0 PPM

Tank 2: Community

Temp: 76 PH 6.5 Nitrite 0PPM Ammonia: 0PPM GH: 75PPM (Soft) KH: 0PPM

Tank 3: Guppy

Temp 76 PH: 8.0 Nitrite: 0 PPM Ammonia: 0 PPM GH: 75 PPM (Soft) KH: 120 PPM

So I'm totally at a loss as to how the Guppy tank developed a higher KH. All three tanks use the same substrate, have about the SAME plant species and all three have driftwood in them. I'm also thinking I need to raise the KH of the Community tank, but I'm not finding a feasible way to do it. I've read about adding limestone to the tank and it will slowly balance. This is great but it's not like the LFS advertises rock types. They just have a huge crate of 'Ornamental Rocks' and it's up to you to pick through. There are rocks in the tanks now but I guess they're not leeching anything to contribute to the KH. Any thoughts?

Chalk board chalk, sea shells, or marble chips (the snow white garden stones). Just put a couple in your power filters.......... Frank

Raising KH but not GH is easy. Just add sodium bicarbonate. Arm & Hammer Baking soda, for example. If you prefer, Kent 'pH-Stable' is the same but with a long- winded alternate name and much increased cost. Since it will dissolve and take effect very quickly, you should take it slow. 6 grams per 50 liters will increase KH by 4 degrees. A good dose might be half a teaspoon (about 2g) per 20 gallons. Measure later in the day and repeat as needed. Note that this will also increase your pH.

Marble chips, seashells, and other forms of calcium carbonate will increase KH and GH but slowly. They do not dissolve quickly in water so it will take you a while to bring up the hardness. I have tried dumped in a few grams of very finely powdered calcium carbonate and found much of it settling out on the gravel or plant leaves, even days later. Frank's suggestion of putting some shells or marble chips inside your filter makes sense. The strong flow around the material would help dissolve it. Also, the lower the pH the faster it will dissolve, counteracting the pH dropping tendency.

Still, the sodium bicarb method is easier and is probably all you need.

With those measurements, I would be concerned about the 0 kH tanks, as they will react very quickly to any outside influence. Keep an eye on your ammonia levels. Check what your test kit actually measures, NH3, NH4 or combined NH3/4. Ammonia in low pH conditions is mostly NH4 and as the pH rises, it converts to the more toxic form NH3. This is of interest when you have conditions of low pH, low buffer and are thinking of raising the pH by adding buffer.

Why your Guppy tank has buffer and the other do not, might be attributed to their diets. Just a guess, but Guppies eat less so there is less aggregate pollution building up to consume your buffer. At the other extreme, Discus usually get high protein meals, and community tanks have a variety of foods dropped in, increasing the potential for waste (acidifying the water). How your Guppy tank's buffer got higher than your tap water could only be explained (I think) by some type of mineral in there (gravel rocks).

With driftwood in the tank, adding baking soda would only be a temporary fix. To keep his pH stable, kH should stay above 4.5dH, which should be done *slowly*. By adding a marble chip or two to the filters, it will *slowly* raise both kH and gH, but also the tanks osmotic pressure....... Frank

Adding a bit of coral gravel will help stabalise your pH. With no kH reading your pH will bounce around like a ping-pong ball.. Slowly add the coral gravel till your kH levels come up to around 4 or 5. This will also bring your pH up so watch for an ammonia spike in the tanks. Once your pH comes up over 6.5 your filter bacteria changes to a new form and this can cause new tank syndrome. Do it slowly and try not move your pH levels more than 0.1 per day. That should help the new bacteria establish alongside the old and reduce the NTS.

We figured the bacteria one out fast as our tap water has no kH either, anyone putting sand in their tanks around us usually ends up with a crashed pH and new tank sysndrome once we start to bring the pH up again.

Are you adding salt to your guppy tank? That will increase your kH and pH in that tank.

Nic Aqua Area

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My understanding is that only marine salt, (salt with calcium carbonates) will increase the gH (and kH and pH), not regular aquarium salt.

In addition to what everyone else wrote, you'll want to be careful of which water conditioners you use. AmQuel or AmQuel + will quickly cause your tank pH to crash. I buy Dry Buffered AmQuel to condition my tank. It'll hold my kH at about 40ppm (still very low) but it keeps it stable

Since I'm setting up a saltwater tank in the near future, I figured I'd take some leftover substrate and put that in a bag in my filter. I'm going to rinse it really well though so I don't get any Marine Salt in the tank.