I've always run my reef tanks with an alkalinity around 10 dKH. The rationale was that this value represented the middle ground in the alkalinity range given in care guides for most corals (8-12 dKH). LPS has done well in my tank as long as I have some detectable nitrates and phosphates. SPS other than Montipora seem to struggle or exist but not thrive. I test frequently, dose aminos and carbohydrates, dose trace elements, do water changes and other routine maintenance, but Acropora and birdsnest really seem to struggle in my tank. I have added calcium hydroxide to my topoff water and trim calcium levels in the tank through dosing for the last 3 years or so.
After exhausting all of the other options and through some encouragement from my local reef club members, over the past two weeks I've been running a test to see if lowering the alkalinity to around 8 dKH would really make a change. I stopped all ATO water additions and have been dripping limewater continuously throughout the test period while using my sodium carbonate solution to round out and stabilize dKH numbers. To my surprise, the tank has really looked much better since I lowered the alkalinity. Not only is polyp extension crazy good right now, even the birdsnest is looking markedly better and the long tentacle anemone is, honestly, the largest I've ever seen him. Thus, the case for change is established.
Right now, the dKH is holding steady around 7.7-7.8. I can only conclude that the lower alkalinity has really helped my tank (hence time to eat crow) since I've held other factors as constant as possible. However, dripping limewater continuously is a major PITA. I've overall mostly matched the drip rate to the evaporation rate through manual trial and error so that salinity has been constant, but there's no practical way for me to drip continuously into the foreseeable future on a 125 gallon system.
So, I have some questions that I hopes some of our peeps might be able to help me get a handle on:
1. The evaporation rate is 2-4 quarts per day, depending on time of year and temperature. Dripping that amount of limewater in not feasible in the long-term, and dosing the better part of a gallon of limewater per day is also not going to work out well for the life of the dosing pump. I have an Apex Classic with an EB8 (no unused outlets...so I'd have to address that), and I was thinking of just setting up a topoff routine where I run the pump for a few seconds several times per day. Does anyone have a better suggestion for dosing that amount of solution each day?
2. I've used standard old Instant Ocean forever, with reasonable results. IO also mixes up a dKH higher than 7-8, so how would one adjust the dKH of the freshly made saltwater before adding it to the system? Can one use hydrochloric acid to adjust the dKH? Is it an iterative procedure or is there a calculation that one can do to estimate the amount of acid required to lower the carbonate hardness to a desired level? I'm scared to death at trying a different salt mix because the last time I tried a different salt (Reef Crystals), it was not a pleasant experience.
3. I recently was reading about Randy's newer two part solution using sodium hydroxide and sodium sulfate. I'm curious about switching to this system eventually, but the transition plan for his classic DIY recipe to this new arrangement is not clear to me. I'm particularly concerned about the sulfate portion as it was tied to magnesium in the past but is now divorced from magnesium additions. How would one make the switch if I decided to do that in the future?
Sorry for the long post and questions. I hope someone will be able to give me ideas on how to proceed going forward. Thanks in advance!
After exhausting all of the other options and through some encouragement from my local reef club members, over the past two weeks I've been running a test to see if lowering the alkalinity to around 8 dKH would really make a change. I stopped all ATO water additions and have been dripping limewater continuously throughout the test period while using my sodium carbonate solution to round out and stabilize dKH numbers. To my surprise, the tank has really looked much better since I lowered the alkalinity. Not only is polyp extension crazy good right now, even the birdsnest is looking markedly better and the long tentacle anemone is, honestly, the largest I've ever seen him. Thus, the case for change is established.
Right now, the dKH is holding steady around 7.7-7.8. I can only conclude that the lower alkalinity has really helped my tank (hence time to eat crow) since I've held other factors as constant as possible. However, dripping limewater continuously is a major PITA. I've overall mostly matched the drip rate to the evaporation rate through manual trial and error so that salinity has been constant, but there's no practical way for me to drip continuously into the foreseeable future on a 125 gallon system.
So, I have some questions that I hopes some of our peeps might be able to help me get a handle on:
1. The evaporation rate is 2-4 quarts per day, depending on time of year and temperature. Dripping that amount of limewater in not feasible in the long-term, and dosing the better part of a gallon of limewater per day is also not going to work out well for the life of the dosing pump. I have an Apex Classic with an EB8 (no unused outlets...so I'd have to address that), and I was thinking of just setting up a topoff routine where I run the pump for a few seconds several times per day. Does anyone have a better suggestion for dosing that amount of solution each day?
2. I've used standard old Instant Ocean forever, with reasonable results. IO also mixes up a dKH higher than 7-8, so how would one adjust the dKH of the freshly made saltwater before adding it to the system? Can one use hydrochloric acid to adjust the dKH? Is it an iterative procedure or is there a calculation that one can do to estimate the amount of acid required to lower the carbonate hardness to a desired level? I'm scared to death at trying a different salt mix because the last time I tried a different salt (Reef Crystals), it was not a pleasant experience.
3. I recently was reading about Randy's newer two part solution using sodium hydroxide and sodium sulfate. I'm curious about switching to this system eventually, but the transition plan for his classic DIY recipe to this new arrangement is not clear to me. I'm particularly concerned about the sulfate portion as it was tied to magnesium in the past but is now divorced from magnesium additions. How would one make the switch if I decided to do that in the future?
Sorry for the long post and questions. I hope someone will be able to give me ideas on how to proceed going forward. Thanks in advance!