Cal -alk and water changes?

[SteveZ15]

Im starting to dose the tank with 2 part.. When you do water changes do you buy salt that closely matches the levels in the dt or do you alter the levels of the water change water to match the dt? if the new mixed salt water is higher than the dt how do i lower it or if its 2 low how do i raise it. should i add 2 part to the new water?I have a 40gal tank mabe 50 or so gals with the sump. I have rowa phos running about 50grams..I add 20 ml of 2 part daily the cal stays 460-480 the alk is around 8.2 but sometimes dips to 7.8..I think it was because i added 15 ml for a few days instead of 20 but the cal didnt drop. I have about 20 frags mostly lps and zoas one sps..I am getting nice coraline .ph 8.2 steady... I want to get to the point where I can add more sps in the future.Im trying to learn not to cause any swings in alk by the things I am doing like water changes and adding 2 part..To me 20ml seems like a lot for a tank with only 20 frags.. do these corals suck up that much?All the corals are healthy and growing.I use reefcrystal salt roid water and test with salifert.The tank is fairly young at 50something days..If the sps take alot more out of the water mabe I should think of using a reactor for cal..Any body with a mixed tank that uses 2 part how much do you use?

 

[Cris007]

What brand of 2 part are you using?, what brand of test kits and also what's your magnesium level at?

 

[Boomer]

Chris
He is using Salifert

Steve

Your Alk demand is higher than your Ca++ demand. So, I would cut back on the Ca++. There is no need to have it that high. Corals do not grow faster at higher Ca++ but usually slower. SLOWLY, bump up the Alk to ~10 dKH. When the Ca++ gets to around 420 - 440 start it back up. Your drop in Alk is more caused by slightly high CO2. More than likely high room air CO2.

When your tank drops 20 ppm Ca++, there will be at least a drop of 2.8 dKH. Other reactions other than corals use Alk. So, that drop may be say 3 dKH / 20 ppm Ca++.

The only issue I see is the high Ca++. Based on your parameters your pH should be ~ 8.28 -8.3 and not much of an issue. I will add your coralline is also using some of that Ca++ and Alk like the corals but also Magnesium, which corals use very little of. You need to check that as Chris mentioned.

 

[SteveZ15]

I Am Using B Ionic .. I Was Getting Mixed Info About Adding The Alk Only Is It Safe To Add Only One Part Of B Ionic Or Should I Find Something Else To Boost Alk. I Am Waiting For Mag Test To Come In I Ordered Kt..I Have A Lot Of Surface Movent From Return And Tank Is Open.I Read That I Shouldnt Add Only One Part I Did In Begining But Started To Add Both

 

[Boomer]

Rather than wasting the B-Ionic for Alk just use Baking Soda. Normally you should add the two parts equally. However, at times there are issues where you can't. Once you are more in line go back to equal 2 parts.

You saw Johnny's post, it is well done and a good guide.

 

[SteveZ15]

yea I read it.I added 22ml alk and 18ml cal. over the next few days if i can bring calc to 450 and the alk closer to nine,til the mag test comes in.Everything is doing well so if I can get it slowly balanced in a week or two. The ph has been 8.2 the whole time,so im pretty close to where I gotta be.I didnt know if the rowa phos was affecting anything but I didnt add a lot I gotta tes phos today to see if I have to add more. its usually .05-.02.. I get some algae on the sand bed but not as much since the rowa.

 

[Boomer]

Ok, sounds good