Long term use of sodium carbonate??

[peterhos]

Greetings All

My new Red Sea reefer is now 5 months old. DKH have dropped from initial 8.9 over the 5 months to today’s 6.7. In the tank I have 12 zoa frags and half a dozen SPS frags which look as if they may be starting to grow/prosper/colour up. So, my plan is to add sodium carbonate to my water change water. I am at home all day so have a routine of changing 1% of the water per day. My LFS that sells good frags has dKH of 8.5. Should I aim to keep the tank at 8.5? Is there anything ‘missing’ if I try to do this with only the sodium carbonate? I would like to keep the tank maintenance simple. My plan above seems simple. But, your opinions and advice will guide me. Thanks all.

 

[Ron Reefman]

Just figure out how much you need to dose on a regular basis and add it.

I have to dose 25ml of Ca and alk (soda ash) every day.

Corals can tolerate a kind of wide range of dKH levels. The sps corals do not like anything less than about a 5.0 to 6.0 dKH which will cause them to die. Soft corals are a bit more tolerant.

 

[Randy Holmes-Farley]

Adding alkalinity to new salt water is generally not a good plan, and that is why it is not generally used.

Here's why.

Say you want to boost alk by 1 dKH per day.

If you change 1% of the water volume each day, then for the new salt water to add 1 dKH, the new salt water will need to be ~100 dKH higher than the tank.

That will never happen without precipitating massive calcium carbonate deposits in the new salt water..

 

[peterhos]

Just figure out how much you need to dose on a regular basis and add it.

I have to dose 25ml of Ca and alk (soda ash) every day.

Corals can tolerate a kind of wide range of dKH levels. The sps corals do not like anything less than about a 5.0 to 6.0 dKH which will cause them to die. Soft corals are a bit more tolerant.

Thank you. I was away for 3 days, unusually, and was surprised to see dKH at 6.7., down 1.2 over a week.

 

[peterhos]

Adding alkalinity to new salt water is generally not a good plan, and that is why it is not generally used.

Here's why.

Say you want to boost alk by 1 dKH per day.

If you change 1% of the water volume each day, then for the new salt water to add 1 dKH, the new salt water will need to be ~100 dKH higher than the tank.

That will never happen without precipitating massive calcium carbonate deposits in the new salt water..

Thank you. In which case, could I add the carbonate to the ATO which replaces around 3 gallons every 3 days. Or could I put it manually into the sump. Or would a doser be the real answer? Incidentally the tank is starting to look good at last. No live rock around here so I wished I had not had to start with some OK looking but uninspring dry rock.

 

[Randy Holmes-Farley]

Thank you. In which case, could I add the carbonate to the ATO which replaces around 3 gallons every 3 days. Or could I put it manually into the sump. Or would a doser be the real answer? Incidentally the tank is starting to look good at last. No live rock around here so I wished I had not had to start with some OK looking but uninspring dry rock.

Yes, an ATO of fresh water can add alkalinity in most forms (not organic ones like all for reef or calcium acetate as bacteria may consume the organic). The only concern is that it will not be steady addition day to day, as evaporation changes, but I did that for 20 years using limewater (kalkwasser) as the only source of calcium and alk for my tank.

 

[peterhos]

Yes, an ATO of fresh water can add alkalinity in most forms (not organic ones like all for reef or calcium acetate as bacteria may consume the organic). The only concern is that it will not be steady addition day to day, as evaporation changes, but I did that for 20 years using limewater (kalkwasser) as the only source of calcium and alk for my tank.

My top up water is RO water …. could I put the carbonate in there? I take your point about differing rates of evaporation. Am now looking at Red Sea doses!

 

[peterhos]

dosers …

 

[Randy Holmes-Farley]

My top up water is RO water …. could I put the carbonate in there?

Yes.

 

[peterhos]

Yes.

Thank you all and Randy. I now have a plan…

 

[Randy Holmes-Farley]

Thank you all and Randy. I now have a plan…

You're welcome.

Happy Reefing.