Dosing Mag/Ca/Alk in large tank

[museumguy]

Just wondering at what levels people keep Mag/Ca/Alk in their large reef tanks and how? I maintain a 1700g reef for my work and I'm finding it difficult to keep Magnesium high enough since without any dosing it sits around 1000-1100. I use ReefCrystals and an automated water changing system which changes about 25-50 gallons of water per day, with the occational 700 or so gallon water change every couple of months.

It is stocked with a wide array of corals with lots of Monti cap, Acros and other LPS and SPS, and Coraline algae is growing very fast as well, all of which I think are contributing to the decline in Mag.

Just wondering if anyone else has had this problem and what they used to fix it. I'm currently dosing Randy's Magnesium recipe but that much water means I have to dose an awful lot. Wondering if anybody has any suggestions or has been through this too.

Thanks!

 

[Typhon]

Well.. I have the same issue. With my 520g tank I normally dose at least a gal of Mag a month. I use to dose more because IO and Reef crystal are know to have low Mag levels. I have started mixing IO with Oceanic to give a better balance.

Also, how is SW mixed for your auto system? Do you see alot of residue at the bottom of the mixing container?

Or is it a dialysis machine?

 

[museumguy]

It is a Dialyseas machine and there tends to be some residue that forms in the bottom of the salt mixing tub. I just go in every little bit and stir it up good, never really have had a problem. One of these days I'll probably empty it and get everything out and start fresh, but I'm not too concerned.

 

[Typhon]

Have you test the Mag level of the Reef crystal? My last RC bucket came up with 1120 Mg levels.

It is a Dialyseas machine and there tends to be some residue that forms in the bottom of the salt mixing tub. I just go in every little bit and stir it up good, never really have had a problem. One of these days I'll probably empty it and get everything out and start fresh, but I'm not too concerned.

 

[museumguy]

I just made a ~4 gallon batch from a bag at 1.024 it tested at 1080 ppm Mag. I realize for most accurate results you need to mix an entire bag but that will have to be done a different time.

 

[Typhon]

IMO, Reef Crystal is pretty consistent. So if you mix 4 gal or 200g it should be the same.

Also, RC is designed to be at 35 ppm salinity. So with the lower salinity and just the fact RC is low in Mag. There is the problem.

If you don't what to add Mag, just switch salts.

I just made a ~4 gallon batch from a bag at 1.024 it tested at 1080 ppm Mag. I realize for most accurate results you need to mix an entire bag but that will have to be done a different time.