Raising Alk, nothing else

The last week or so some of my corals are looking a bit worse for wear, i have accumilated a abundance of corals in the 5 months its been running, mostly frags,

Colt coral
various zoas
mushrooms
gsp
hammer, 3 head
yellow polyps
lobophilia, 3 head
ricordia
2 head candy cane
yellow gorgonian

i water change 25% every week
my params are
Temp-76f
Salinty-1.024
Ammonia-0
Nitrate-1
Nitrite-1
phos-0.025
calcium-420
mag-1250
PH-8.0
Alk-7

Cant find anything wrong, is the alk to low and if so how can i raise it on its own, i do have a cyano outbreak at the moment that im fighting, adding phos reactor today, 150watt 14k halide on 8 hours a day,

1 coral beauty and 1 small clown/chromis,

im puzzled
Thanks guys

 

I would use the reef calculator to find out how much baking soda you need to bring the alk up. Adding it slowly.

 

I agree. I would raise it a little.Also your PH will be different depending on the time of day.It usually reaches its peak in the afternoon/evening. Test your PH in the morning before the lights come on.If it is dropping to far(which can occur when Alk. is low) this could be your problem.I would be a bit alarmed about the Phosphate reading (cyano)as well.

 

Thanks guys, i have been adding 1 teaspoon of bicarbonate of soda daily in top up water, slower raising it to 9 now, sine i added my tlf reactor and 1 cm of rowaphos, the phosphates are showing 0 now, cyano is a more orangey colour them red now, is it worth me adding a light to the sump and placing some cheato in there?

 

I think adding chaeto and a light in the sump is a good idea as far as a nutrient export.

 

You listed your Nitrite as reading 1. Is that correct? If so, then there's your problem. Nitrite is as toxic as Ammonia.

 

Sorry guys or gals lol, Nitrite is 0, my bad

Tested Alk today after adding bicarbonate of soda, 1 teaspoon with top off water over 5 days, its now a comfortable 10,

Problem is it seems to have dropped my calcium to 350ppm and 1150 Magnesium, one goes up one goes down grrrr,

I'm guessing i need to get the mag up first to 14-1500, im going to use epsom salts and carb of soda for alk, what should i use for calcium, i did get a bottle of liquid calcium in my salt barrel

Its 250ml 3.+++ biotope animal by aquarium systems

 

Your Mag. level should be roughly three times your calcium level.So if you are aiming for a 400 cal. Mag. should be around 1200.

 

An Alk of 7 is also is acceptable range, IMHO

 

I agree, but all the corals to me seem to do better with 8-10 alk in my tank, the zoas have started to multiply again since I raised it, I have a lot of lps
I was thinking mag 1400 calcium 450, alk 10 for optimal parameters