New Tank, Low Alkalinity

[Dj A-Ron]

Set up my tank on August 23rd and am using Tropic Marin Pro reef salt. Before starting the cycle the Alkalinity tested at 7.5 with the Hanna checker. I started doing a fishless cycle on August 28th using Dr. Tim's bacteria and ammonium chloride. By September 1st the Alkalinity dropped to 6.5, Phosphate = 0.03, Calcium = 434. I set up the Neptune DOS to do 1 gallon per day water changes so about 10% water changes per week. I was having pretty low PH readings during this time of between 7.5-7.8. I figured that high C02 concentration in the house was the cause of my low PH since I also have a high tech planted tank running C02 injection in my home. Opening windows helped the PH problem so I installed a C02 scrubber to my tank yesterday which now the PH is sitting around 8.0-8.1. Last night I decided to do some testing of the water just to see where everything is sitting. Here are the results of my test:

Salinity = 34.1 (Hanna). 34.4 (Apex)
PH = 8.1 (Apex)
Temp = 78.1 (Apex)
Alkalinity = 5.7 (Hanna)
Phosphate = 0.14 (Hanna)
Calcium = 484 (Hanna)
Ammonia = 0.0 (Salifert)
Nitrite = 0.0 (Salifert)
Nitrate = 25 (Nyos)

I have a saltwater mixing station set up with the two Brute trash cans. I have a pump in the saltwater container that runs every two hours for 30 minutes to keep the water moving every so often. This water has always tested at 35ppt Salinity in the container. I plan to test the Alkalinity of the source water tonight, but I suspect it to come out at 7.5

Again, this is a new tank and I have no live stock in the tank and am doing a fishless cycle. I have two clown fish in quarantine for at least another 2 weeks so I'm just trying to dial in the tank to have it stable and ready for the fish. Since I'm doing the 1 gallon daily water changes I'm kinda puzzled on why the Alkalinity is so low seeing as though I have no live stock in the tank....

Should I even be worrying about this or should I not bother until fish are in the tank? I am new to saltwater so any help or suggestions would be greatly appreciated.

Thanks in advance

 

[Daddy-o]

I dont understand why your alk. puzzles you? Tropic Marin has an alk. of 7

 

[Billdogg]

^^^This^^^

although I don't know why it would be going down. I'd be interested in what your Magnesium is. If it's low it's pretty much impossible to bring Alk up.

 

[Saltyreef]

+1 to the mag comment.

 

[Dj A-Ron]

Again, I'm new to saltwater so I'm just trying to understand how the parameters coincide. It puzzles me because from all the research that I've done, doing water changes is supposed to keep things stable or replenish used elements. Seeing as though I have nothing but rock and sand in the tank I'm just wondering and asking why it may be dropping. I know and you say that Tropic Marin has an Alk of 7 so why might it drop to 5.7 while doing auto 1 gallon water changes per day....?

 

[Dj A-Ron]

I do not have a Magnesium test kit yet but I will get one. Thank you for that advise. Any advice on which Mag test kit is best? I've read that the Aquaforest is one of the better kits.

 

[vetteguy53081]

Unless you have corals and mainly acro- I would be too concerned with the tank in cycle. However, I would get a second opinion on your tests from a trusted LFS to compare with your readings.

 

[cshouston]

Set up my tank on August 23rd and am using Tropic Marin Pro reef salt. Before starting the cycle the Alkalinity tested at 7.5 with the Hanna checker. I started doing a fishless cycle on August 28th using Dr. Tim's bacteria and ammonium chloride. By September 1st the Alkalinity dropped to 6.5, Phosphate = 0.03, Calcium = 434. I set up the Neptune DOS to do 1 gallon per day water changes so about 10% water changes per week. I was having pretty low PH readings during this time of between 7.5-7.8. I figured that high C02 concentration in the house was the cause of my low PH since I also have a high tech planted tank running C02 injection in my home. Opening windows helped the PH problem so I installed a C02 scrubber to my tank yesterday which now the PH is sitting around 8.0-8.1. Last night I decided to do some testing of the water just to see where everything is sitting. Here are the results of my test:

Salinity = 34.1 (Hanna). 34.4 (Apex)
PH = 8.1 (Apex)
Temp = 78.1 (Apex)
Alkalinity = 5.7 (Hanna)
Phosphate = 0.14 (Hanna)
Calcium = 484 (Hanna)
Ammonia = 0.0 (Salifert)
Nitrite = 0.0 (Salifert)
Nitrate = 25 (Nyos)

I have a saltwater mixing station set up with the two Brute trash cans. I have a pump in the saltwater container that runs every two hours for 30 minutes to keep the water moving every so often. This water has always tested at 35ppt Salinity in the container. I plan to test the Alkalinity of the source water tonight, but I suspect it to come out at 7.5

Again, this is a new tank and I have no live stock in the tank and am doing a fishless cycle. I have two clown fish in quarantine for at least another 2 weeks so I'm just trying to dial in the tank to have it stable and ready for the fish. Since I'm doing the 1 gallon daily water changes I'm kinda puzzled on why the Alkalinity is so low seeing as though I have no live stock in the tank....

Should I even be worrying about this or should I not bother until fish are in the tank? I am new to saltwater so any help or suggestions would be greatly appreciated.

Thanks in advance

Hello! The nitrogen cycle consumes carbonate alkalinity as it proceeds along the chain. Your nitrifying bacteria is what is depleting the Alk in your system. This kind of instability is why corals aren’t recommended until a tank is properly matured. Once the system finds an equilibrium, the alkalinity consumption from nitrification won’t be an issue. It’s returned to the system when the nitrate is otherwise utilized or consumed—by macro algae for example.

“During nitrification, 7.14 mg of alkalinity as CaCO3 is destroyed for every milligram of ammonium ions oxidized.”

 

[Dj A-Ron]

Hello! The nitrogen cycle consumes carbonate alkalinity as it proceeds along the chain. Your nitrifying bacteria is what is depleting the Alk in your system. This kind of instability is why corals aren’t recommended until a tank is properly matured. Once the system finds an equilibrium, the alkalinity consumption from nitrification won’t be an issue. It’s returned to the system when the nitrate is otherwise utilized or consumed—by macro algae for example.

“During nitrification, 7.14 mg of alkalinity as CaCO3 is destroyed for every milligram of ammonium ions oxidized.”

Thank you so much! This is the informative information that I was looking for. So just leave everything alone is what you are saying correct? LOL

 

[Dj A-Ron]

I went to my LFS and all they had was a Salifert Magnesium test kit. I tested the tank and the magnesium is 1320

 

[SaltISlife]

If that salt has sn alk of 7 to me thats too low to begin with. I tty to keep my alk at 9-10 at least. And reef crystals has an alk of like 12 or 13 to start off with.

Remember though alk mag and calcium all coincide with eachother. With an alk of 7 i would expect calcium should be more in the 380 range give or take