low kh

[chimera]

my kh is low, at about 6, but not overly major as i have very few sps at the moment. i havent measured ph for a while but i would imagine lack of buffering will mean its getting too low? if my calcium reactor is dripping 40dpm running 24x7 (havent tested kh coming out of it, but assume its about 20? - i believe you should aim for around 30 once the reactors "broken in") how long will/should it take 1,000 litres to get up to kh of about 8.5? i obviously dont want to raise this too quickly, so co2 bpm is only about 10 (which instructions say to start with) how quickly can you up the kh and what is defined as "too fast?"

An interesting excerpt from Randy Holmes-Farley on discussion of Alkalinity:

Finally there is the German term dKH (degrees of carbonate hardness), or just KH (carbonate hardness).Strictly speaking, it is the same as the carbonate alkalinity (AC in equation 8 ). Unfortunately, it is a very confusing term, as it has nothing to do with hardness. Further, it has been corrupted by the marine aquarium hobby to mean the same as total alkalinity, and every test kit that tests for dKH with a single titration is giving total alkalinity. The only kit that I am aware of that even makes a distinction between carbonate alkalinity and total alkalinity is one of the Seachem kits (Reef Status: Magnesium, Carbonate, & Borate) and it thankfully doesn’t use the term dKH at all. Consequently, most hobbyists should think of dKH as simply another measure of total alkalinity. The results obtained with such a kit (dKH) can be divided by 2.8 to yield the alkalinity in meq/L.

http://www.advancedaquarist.com/issues/feb2002/chemistry.htm

[wasp]

kh and calcium move up or down together, so a good reactor media will make both kh and calcium in the correct balance. Therefore, if your calcium is already where you want it, the way to increase kh without affecting calcium would be to add a seperate kh supplement such as baking soda until your kh is where you want it. Thereafter maintain both with your reactor.

Here is a good read http://reefkeeping.com/issues/2002-04/r ... /index.htm

and http://www.advancedaquarist.com/issues/nov2002/chem.htm

[chimera]

cheers, already read the first one. i havent tested calcium levels separately but last time i did (several weeks ago) it was a little low too, so dosing from the calcium reactor should theoretically overtime increase both calcium and alkalinity to better levels. question was, how long this should or will take? guess its a hard question to answer and I would imagine it should be achieved slowly over several weeks or more. is it safe to increase either co2 bpm and/or effluent dpm?

[wasp]

How long it takes depends entirely on how much calcium and dkh your tank is consuming.

So as you have a newish tank, calcium and dkh should be measured weekly so you can see if these levels are moving in the direction you want. Also, over time as your sps, coraline, and other calcium needing organisms increase, you will also have to increase the amount you are supplementing to the tank. If the reactor cannot keep up, you could do this by additionally adding kalk, or a 2 part mix.

[Pies]

My KH is 8.3, Calcium 440. I have never tested my efluiant but there are heaps of tips for korallin reactors and tank sizes. So just match your driprate/bubble rate to that and let it be. Well its worked for me.

I also have 10% of my media is the magnesium stuff from brendon, I am still doing magnesium a little but not as much. I quite like having to top off just a little mg.

Piemania.

[chimera]

cheers. the actual tank is new, but the water parameters are not (the 5 footer used to be a 4 footer which had been around for several years) reactor will easily keep up as it's rated for up to 2,500 litres i already am and have been dosing kalk for the last 6 months.

pies, i also have about 10% magnesium chips in the top of the reactor (see the different colour on the pic )