How much can water parameters fluctuate and be fine?

[Schraufabagel]

My tank currently consumes 0.2 dkh per day and roughly 10 ppm Ca and 10 ppm Mg per week. I use Red Sea Coral Pro salt which has 11.5 dkh, 450 ppm Ca, and 1350 ppm Mg. Without a water change during a week the dkh would drop by 1.4 along with 10 ppm Ca and Mg. Is this fine if the water change is done? Or does that much fluctuation irritate corals? Ultimately I'm looking at auto dosing and this would decide if 2 channels is fine or if I should do 4. This is for a 25 gallon tank

 

[Spare time]

I don't think there is as solid answer. Personally, I like to start dosing once the coral starts consuming over .5-1KH a week. BRS says never to raise KH more than 1.4KH at a time, but I am not sure if this has to do more with pH or KH. I think something like all for reef would work for your tank, or a simple 2 part solution (I would say based this off of whether or not your pH averages above 8 or not). I am not sure why you would need a 4 channel doser given that your water changes will be more than enough for magnesium (and I also am not sure what the 4th would be for).

 

[dedragon]

If youre not dosing and not having an issue I would probably stick to all for reef for the moment as well. 1 dosing pump and done just monitor the calcium and magnesium changes for the first couple of weeks after to make sure everything is keeping up with alk

 

[Schraufabagel]

I don't think there is as solid answer. Personally, I like to start dosing once the coral starts consuming over .5-1KH a week. BRS says never to raise KH more than 1.4KH at a time, but I am not sure if this has to do more with pH or KH. I think something like all for reef would work for your tank, or a simple 2 part solution (I would say based this off of whether or not your pH averages above 8 or not). I am not sure why you would need a 4 channel doser given that your water changes will be more than enough for magnesium (and I also am not sure what the 4th would be for).

I use ChaetoGro daily for my refugium. I'll look into All for Reef or 2 part and see how difficult it would be