I had been dosing soda ash at night from 8 PM (around lights out) to 11 AM when lights began ramping up, with calcium on the opposite schedule. I stopped doing this because I noticed my alk during the end of my photoperiod was swinging quite a bit lower than during morning when I always made a point to test it. I use a hanna checker to test and get pretty consistent results, usually within one decimal point of each other when I have my dosing tuned "right". I adjusted dosing often to try and maintain very stable alk. I have a 25g lagoon with a 10g volume of water in the sump (25g sump) and many acros, some of which are beginning to be mini colonies.
One example of a test would be 8.3 at 730 AM and 7.8 at night around 8 PM. So in order to try and counter this, I set my Neptune DOS to dose Ca and Alk throughout the day, with a minute offset so they wouldn't dose at the same time and precipitate. They drip into a raceway in my sump with a COR-20 at full flow so no issues of low flow on that.
Last night I did a test and freaked out when I saw my alk at 7.6. I had missed two mornings of Alk testing and i was at 8.5 last I tested. So i upped the dosing from 23.5->25 mL (which is the reverse of the change I had made before my last test since 8.5 was a bit high for me) and tested again this morning. It was back to 8.3. It's possible that last night's test was just a bad reading (and within the precision/accuracy of the hanna anyways, probably right? Though I find it to be quite repeatable usually when done carefully), but it raises to a point my dilemma on how to dose in this system.
What is the optimal way I should be dosing to avoid daily alk swings? My pH swings from 8.1 at trough to 8.4 at peak. I run nothing to counteract pH other than an airline on the skimmer outside.
Secondary question, I have often needed to dose calcium at higher levels then I do my soda ash to keep it from dropping. Numbers like 28 mL Ca to 23.5 mL soda ash.
One example of a test would be 8.3 at 730 AM and 7.8 at night around 8 PM. So in order to try and counter this, I set my Neptune DOS to dose Ca and Alk throughout the day, with a minute offset so they wouldn't dose at the same time and precipitate. They drip into a raceway in my sump with a COR-20 at full flow so no issues of low flow on that.
Last night I did a test and freaked out when I saw my alk at 7.6. I had missed two mornings of Alk testing and i was at 8.5 last I tested. So i upped the dosing from 23.5->25 mL (which is the reverse of the change I had made before my last test since 8.5 was a bit high for me) and tested again this morning. It was back to 8.3. It's possible that last night's test was just a bad reading (and within the precision/accuracy of the hanna anyways, probably right? Though I find it to be quite repeatable usually when done carefully), but it raises to a point my dilemma on how to dose in this system.
What is the optimal way I should be dosing to avoid daily alk swings? My pH swings from 8.1 at trough to 8.4 at peak. I run nothing to counteract pH other than an airline on the skimmer outside.
Secondary question, I have often needed to dose calcium at higher levels then I do my soda ash to keep it from dropping. Numbers like 28 mL Ca to 23.5 mL soda ash.
