Dosing with autowater changes

[DiverDave32]

Hi,

I just started dosing Kalkwasser and also using two part. I have successfully increased both my calcium levels and magnesium to where I want them (420 and 1320 ppm). My Alk is a little low right (7.2 dKh) now but will continue adjusting.

My system is set-up to do autowater changes of about 2% of the water volume everyday. This water is pumped into my quarantine tank where it overflows into a reservoir and is pumped out automatically.

What I was wondering is if I could actually get away just boosting the Ca, Alk and Mg in the salt water reservoir when I make it which lasts about 2 weeks and stopping dosing the Kalk, Ca, Mg and Alk in the aquarium. The reservoir lasts about 2 weeks. This would be much simpler than having two reservoirs (ATO and Kalk to manage). Any disadvantages besides not having the pH boost of Kalk at night?

Thanks,

Dave

[ramseynb]

I would worry about precipitation of calcium if you loaded up your NSW with 2-part/kalk.

[DiverDave32]

I would probably stop using the Kalk and only use 2-part so I may boost the alk to 10 and calcium to 450 ppm in the reservoir but I would need to do some fine tuning.

[bertoni]

That's probably not going to work for most tanks because raising the alkalinity or calcium very much will cause precipitation of calcium carbonate. I'm not sure how high you could push it, but something like 18 dKH might be getting very close to the limit, depending on a number of factors. Tanks that have very low demand might be fine with that.

[DiverDave32]

It is mostly soft coral tank and LPS for now. I was thinking of boosting the alk to around 10 or so. Since I am doing a 2% water change per day, I hope that this will be able to maintain my levels. I guess I will try it and see if it works for my particular conditions, if not, I will just dose the 2 part directly to the tank but adjusting once every two weeks would be really easy and nice if it works.

[bertoni]

It might be fine. We can compute the amount of water that'd need to be changed based on current consumption, but giving it a shot will be fine as long as you watch the alkalinity level carefully.

[ramseynb]

Personally, I think your alk level is fine. Why are you wanting to raise it?

EDIT:

http://www.reefkeeping.com/issues/2004-05/rhf/index.php

Check out the number for sea water. Alk is 7.

[DiverDave32]

I'll give things a little bit of time to stabilize and will see now that I am approaching my target levels what the consumption is under these conditions and make small adjustments as needed.

I was aiming to raise my Alk as it is at the bottom of the range and thought that being more towards the middle might be better. It will also increase my corraline algae which wasn't growing much and hopefully it will outcompete the algae.

My parameters are quite good with 0 PO4 (Hanna checker) and 4 ppm Nitrate. I know that the PO4 is being bound by the Algae. I also have replenished some of my clean-up crew that had committed suicide over the years by falling on their backs which should help.

Thanks for the feedback.