AFHokie
Active Member
Before I post my question I'll point out that I have used search and read many posts on this issue but none seem to have an answer that makes sense in my tank.
Several weeks ago I noticed (for second or third time over a few months) that my Alk was increasing despite no change in my AFR dosing from months prior. The first spike I attributed to either reduced lighting and thus reduced uptake without a commensurate reduction in AFR or to an overdose of lime paste I used to kill a few aiptaisia (very small amount so I doubt this was it but I had no other explanation). More recently though my lights have been ramping up, so that wouldn't be the cause and it got me wondering why my Alk consumption seemed to be dropping therefore making my Alk rise as result of the dosing.
To validate my reading I decided to completely stop AFR dosing. After a few days to account for the AFR lag I was still seeing no drop in Alk. That's when I started doing my google searches. I can clearly see coral growth (leptoseris, multiple favites, chalice) so there should be demand yet my Alk is going up, rather than down. Ca has been slowly depleting, around 5 ppm per week if I remember right (no log in front of me). My searches on here eluded to nitrogen dosing or certain supplements/food raising alkalinity so I stopped any of those. I was using Reef Energy AB+ and very infrequently neo Nitro/Phos if those numbers were dropping and feeding wasn't bringing them up. My tank is 6 months old, started from dry rock, no hard sand chunks that I've noticed (4 super nassarius are keeping stirred to some degree). Also no major drops in NO3.
To bring my Alk down and further validate what I was seeing I performed small water changes with low Alk water to bring my Alk from 9.9 to around 9.6. All Alk measurements (salifert) have been dead on with what I've calculated with math. Every time I've reduced the Alk with a water change within two days it's right back to around 9.9-10. I've done this three times, and each time the same. The first time I figured there could be test error but after three times every reading is coming out the same. These are freshly mixed batches of water, not the same one partially used. My tank reads 9.9-10, new water reads 6 (2gal) or 4.5 (1gal), resulting tank Alk 9.5-9.6. About two days later Alk test is back to 9.9-10. I haven't let it go for a lot longer to see if it continues rising but for just a couple days it seems to stall at that 9.9-10 mark.
What gives? No dosing. Feeding fish Xtreme pellets and Rod's food. Purposely reducing Alk via H2O change. Coral is growing. Alk still rising.
Could there be a lag in alkalinity with my new salt water? After mixing and at time of change it read the 4.5 or 6 but could that be rising later and by the time it does it's in the tank?
Been monitoring this phenomenon for about two weeks now so below params are just a point in time:
Total vol: 20 gallons
SG: 1.026
Temp: 78.5
Alk: 9.9
Ca: 430
Mg: 1350ish (no log in front of me)
NO3: 5-10 (with the exception of a drop to 0 a few weeks ago it's been in this range for the entire time I've had livestock)
PO4: .05-.07
No skimmer
No reactors or any other "gadgets"
I know lots of people keep their tank at 10 with no issue but each time I've noticed my coral looking a little annoyed it's been when the Alk is higher. Could just be lower nutrients combined with the higher Alk. I do not need a specific number but I'd really love to not worry about my Alk continually rising if I do nothing and don't want to be a slave to daily Alk testing.
Several weeks ago I noticed (for second or third time over a few months) that my Alk was increasing despite no change in my AFR dosing from months prior. The first spike I attributed to either reduced lighting and thus reduced uptake without a commensurate reduction in AFR or to an overdose of lime paste I used to kill a few aiptaisia (very small amount so I doubt this was it but I had no other explanation). More recently though my lights have been ramping up, so that wouldn't be the cause and it got me wondering why my Alk consumption seemed to be dropping therefore making my Alk rise as result of the dosing.
To validate my reading I decided to completely stop AFR dosing. After a few days to account for the AFR lag I was still seeing no drop in Alk. That's when I started doing my google searches. I can clearly see coral growth (leptoseris, multiple favites, chalice) so there should be demand yet my Alk is going up, rather than down. Ca has been slowly depleting, around 5 ppm per week if I remember right (no log in front of me). My searches on here eluded to nitrogen dosing or certain supplements/food raising alkalinity so I stopped any of those. I was using Reef Energy AB+ and very infrequently neo Nitro/Phos if those numbers were dropping and feeding wasn't bringing them up. My tank is 6 months old, started from dry rock, no hard sand chunks that I've noticed (4 super nassarius are keeping stirred to some degree). Also no major drops in NO3.
To bring my Alk down and further validate what I was seeing I performed small water changes with low Alk water to bring my Alk from 9.9 to around 9.6. All Alk measurements (salifert) have been dead on with what I've calculated with math. Every time I've reduced the Alk with a water change within two days it's right back to around 9.9-10. I've done this three times, and each time the same. The first time I figured there could be test error but after three times every reading is coming out the same. These are freshly mixed batches of water, not the same one partially used. My tank reads 9.9-10, new water reads 6 (2gal) or 4.5 (1gal), resulting tank Alk 9.5-9.6. About two days later Alk test is back to 9.9-10. I haven't let it go for a lot longer to see if it continues rising but for just a couple days it seems to stall at that 9.9-10 mark.
What gives? No dosing. Feeding fish Xtreme pellets and Rod's food. Purposely reducing Alk via H2O change. Coral is growing. Alk still rising.
Could there be a lag in alkalinity with my new salt water? After mixing and at time of change it read the 4.5 or 6 but could that be rising later and by the time it does it's in the tank?
Been monitoring this phenomenon for about two weeks now so below params are just a point in time:
Total vol: 20 gallons
SG: 1.026
Temp: 78.5
Alk: 9.9
Ca: 430
Mg: 1350ish (no log in front of me)
NO3: 5-10 (with the exception of a drop to 0 a few weeks ago it's been in this range for the entire time I've had livestock)
PO4: .05-.07
No skimmer
No reactors or any other "gadgets"
I know lots of people keep their tank at 10 with no issue but each time I've noticed my coral looking a little annoyed it's been when the Alk is higher. Could just be lower nutrients combined with the higher Alk. I do not need a specific number but I'd really love to not worry about my Alk continually rising if I do nothing and don't want to be a slave to daily Alk testing.
