assistance raising KH

That is incorrect, gh and kh are two different things. Kh is the measure of carbonates in the water, GH is the ammount of calcium and magnesium in the water.

Sorry can't help too much on the other stuff, I'm still learning this stuff too.

I'm in the same situation. My tap's KH is 1 or 2. I use aragonite in my filter and it has been steady at 3-4. I just added more today in hopes of keeping it around 5 or 6 because I'm starting DIY CO2. So far the aragonite has been working great.

I have rams, therefore I try to keep my gh down to 3-4. This is VERY soft and I use nearly 100% RO water with added RO Right. Now, the kh needs to be high enought to prevent ph swings, so I add 1/8 teaspoon baking soda whenever it gets to low. (I have a 10g)

Start adding the soda very slowly - I hate to tell you this, but it will raise your pH... BUT when you add the CO2, it will come back down... there is a balance and you will need to do frequent testing to prevent disaster from happening while you learn this balance! I mix/dissolve the baking soda in some tank water and pour it in slowly.

I know others put crushed coral in the filter box, I like the control of using a bit of baking soda.

Cathy G

Baking soda will raise your kH.
Crushed coral will raise your kH, albeit more slowly and in a less predictable fashion than baking soda. It will also raise your gH.

Both will also raise your pH.

I use a combination of both. CC in the cannister and baking soda with each 50% WC.

If you want to know the particulars, look here, which IMO is one of the best web pages on planted tanks: http://www.rexgrigg.com/waterchem.htm

what are the pros and cons of of baking soda and crushed coral- is one more stable than the other or longer lasting?

Click to expand...

Baking soda (Sodium bicarbonate)

Pro's:
1. Rapidly dissolves for nearly instant results
2. Will work at higher pH levels than crushed coral
3. Is fairly controllable and stable
4. Cost is relatively low
Cons:
1.Dissolves rapidly which causes rapid changes and should be use with extreme caution in water with fish in it. It's best to mix it in seperate containers and then add small amounts at a time.
2.In addition to the desired carbonate you add sodium rather than something useful and necessary
3. ?baking soda will dissolve even at very high pH levels, so the risk of dangerously high pH does in fact exist.

Calcium Carbonate (CaCo3) Crushed coral, aragonite, limestone, dolemite etc. May also contain some Magnesium Carbonate.

Pro's:
1. Dissolves very slowly, making it safe and stable in the tank system.
2. Increases dissolution rate as pH decreases. which means if you pH drops the coral will dissolve faster to help counteract the drop.
3. Usually slow or stops dissolving at about 7.6-7.8 pH (aragonite seems to go a little higher) so no worries of creating a high pH.
4. Most fish (not all) plants and invertibrates need the calcium and magnesium anyhow.

Cons:
1. Takes a while to dissolve so it tests the patience of someone trying to adjust things.
2. Less controllable by actual amounts especially with co2 injection
3. various different forms dissolve at different rates which makes them more confusing to use (IMO). i.e. a pound of limestone will not have nearly the effect that a pound of crushed coral might, and Aragonite or dolemitic lime will produce much more rapid results than crushed coral.

As far as stability, Coral in a system will create a more atable system, because of it's ability to replenish used buffer at a continual rate. Carbonate in either form will be pretty much the same for stability and longevity in the technical sense. I have used both and keep both but seldom if ever do I use the baking soda. I have to dose magnesium and calcium into my water anyhow, so it makes little sense for me to add carbonate via the baking soda method.

Dave