Need help understanding dosing numbers

ZipAdeeZoa · Sep 25, 2021

Hello everyone!

Full disclosure I've been putting off setting up dosing for a long time, I found the concept very intimidating and really thought water changes where enough- they aren't with the amount I have;Dead Tank is a 13.5 gallon fluval evo that has been running for 2ish years.

I have an ecotech versa, I bough some pharmaceutical grade kalkwasser and mixed it into RODI as per instructions. I have the Ecotech versa and when I started and checked my alk it was 6.7, I also tested my mag and it was really really low... 1050 according to Aquaforest. I started dosing 20 ml's of red sea's magnesium every day and after 3 days of that with no noticeable change in magnesium according to the test kit I upped it 30 ml's a day but still haven't been able to get higher result on the mag test. Similarly I started dosing a very small amount of kalk (2 mls per day) and after not seeing any change in alk I upped it to 5 mls a day. At that dosage my alk has steadily been dropping... 6.7 then 6.5- I upped the dose to 10 mls a day and two days into this dose my alk 5.7 today according to my Hannah checker (also fairly confident I'm doing that right, I use one at work and have never had any issues getting accurate readings).

My theory is that the corals having deprived of these resources for so long and not having sufficient mag to properly use what little alk they've had that they are consuming it at an above average rate. I really don't think thats how it works but I really don't have any other ideas and I'm hoping I can get some clarity on why this might be happening and how much kalk and mag I should be dosing. I'll be honest with you all math is my achilles heal so please dumb down any suggestions as much as you can;Blackeye

Thanks in advance!

T-J · Sep 25, 2021

Do you have a lot of stony corals in the tank?
The best way to determine dosing is to take an alk test, then 24 hours later, take another test (at the same time as the prior one). The difference in the two will show you the daily consumption. Then you dose based on the difference. So, if it dropped by 1 in 24 hours, you need to dose (based on what you're using and the tank volume) for that difference.

arking_mark · Sep 26, 2021

A 13.5 gal tank would require 40ml of saturated Kalkwasser to raise the Alk by 0.1dKH. You can use a reef calculator...

Reef Chemistry Calculators

Reef chemicals calculator Reef Chemistry Calculator Calcium Reactor setup calculator (CaCO3/CO2 reactors) Calcium Reactor Setup Help Aquarium System Volume Calculator Aquarium System Volume Calculator Alkalinity Unit Conversion Calculator SaltyZoo's Alkalinity Reading Conversion (meq/l / dKH...

www.reef2reef.com

A typical mature tank with coral will consume 0.5 to 4.5 dKH per day.

Assuming your measurements are not too off (hobby-grade stuff is very prone to error), I'd take the following approach:
1. Get parameters back to normal with several larger water changes over the next two weeks (20 - 30% water changes).
2. Measure actual Alk consumption over a week to understand how much to dose and use a reef calculator to get actual numbers.
3. Consider switching to an all-in-one supplement such as All-for-reef to simplify your dosing.

ZipAdeeZoa · Sep 26, 2021

T-J said:
Do you have a lot of stony corals in the tank?
The best way to determine dosing is to take an alk test, then 24 hours later, take another test (at the same time as the prior one). The difference in the two will show you the daily consumption. Then you dose based on the difference. So, if it dropped by 1 in 24 hours, you need to dose (based on what you're using and the tank volume) for that difference.

I don't have an exact head count but I have at least 4-5 small blasto frags, 5-6 hammers, a duncan and 4-5 acans for lps. The rest are all softies.

That part makes sense however what I'm not understanding is why only when I started doing has my alk been dropping mush faster, I guess I'm actually creating an environment where the corals can consume it?

ZipAdeeZoa · Sep 26, 2021

arking_mark said:
A 13.5 gal tank would require 40ml of saturated Kalkwasser to raise the Alk by 0.1dKH. You can use a reef calculator...

Reef Chemistry Calculators

Reef chemicals calculator Reef Chemistry Calculator Calcium Reactor setup calculator (CaCO3/CO2 reactors) Calcium Reactor Setup Help Aquarium System Volume Calculator Aquarium System Volume Calculator Alkalinity Unit Conversion Calculator SaltyZoo's Alkalinity Reading Conversion (meq/l / dKH...

www.reef2reef.com

A typical mature tank with coral will consume 0.5 to 4.5 dKH per day.

Assuming your measurements are not too off (hobby-grade stuff is very prone to error), I'd take the following approach:
1. Get parameters back to normal with several larger water changes over the next two weeks (20 - 30% water changes).
2. Measure actual Alk consumption over a week to understand how much to dose and use a reef calculator to get actual numbers.
3. Consider switching to an all-in-one supplement such as All-for-reef to simplify your dosing.

I always forget that there is calculator for that stuff, thank you for the reminder! I'm. not going to lie I had it in my head that kalk was much more potent than that for some reason, I'm going to need a much larger container. I have been looking into all for reef however it doesn't seem to the easiest thing to track down in Canada, it does sound ideal although I'm not sure how well its going to scale up to the Reefer 170 I'm prepping to upgrade to.

I'm thinking tomorrow that I'll do the mag test with the red sea mag supplement to make sure I can actually get a reading that differs from what I've been doing.

at the moment I do one 4 gallon water change a week with red sea Coral pro which was seeming to keep the alk somewhat stable in the absence of mag anyway. Would you recommend I up that to twice a week for a little bit or should I do a series of 2 gallon water changes?

Appreciate all the help!

T-J · Sep 26, 2021

ZipAdeeZoa said:
I don't have an exact head count but I have at least 4-5 small blasto frags, 5-6 hammers, a duncan and 4-5 acans for lps. The rest are all softies.

That part makes sense however what I'm not understanding is why only when I started doing has my alk been dropping mush faster, I guess I'm actually creating an environment where the corals can consume it?

I could be wrong, but I believe know calcium and alk can precipitate out. There's info on here about that.

arking_mark · Sep 26, 2021

ZipAdeeZoa said:
I always forget that there is calculator for that stuff, thank you for the reminder! I'm. not going to lie I had it in my head that kalk was much more potent than that for some reason, I'm going to need a much larger container. I have been looking into all for reef however it doesn't seem to the easiest thing to track down in Canada, it does sound ideal although I'm not sure how well its going to scale up to the Reefer 170 I'm prepping to upgrade to.

I'm thinking tomorrow that I'll do the mag test with the red sea mag supplement to make sure I can actually get a reading that differs from what I've been doing.

at the moment I do one 4 gallon water change a week with red sea Coral pro which was seeming to keep the alk somewhat stable in the absence of mag anyway. Would you recommend I up that to twice a week for a little bit or should I do a series of 2 gallon water changes?

Appreciate all the help!

Think of it this way. If you did a 100% water change with a quality salt, your water parameters should be near perfect.

This is quite easy to do on a 13.5gal tank. The problem with a 100% water change is with parameter stability. You don't want to correct things too fast.

I'd do 4 water changes over a week: day 1 = 30%, day 3 = 40%, day 5 = 50%, day 7 = 60%. This would change out over 90% of your water and correct your parameters to good enough.

Then track your consumption and dose appropriately.

I'd also measure your your salt mix to ensure your testing results are reasonable.

ZipAdeeZoa · Sep 26, 2021

T-J said:
I could be wrong, but I believe know calcium and alk can precipitate out. There's info on here about that.

It definitely can although I forget the specifics of why it does, I should probably re familiarize with the cause of that, that may not be whats happening here buts its something I will for sure keep in mind

arking_mark said:
Think of it this way. If you did a 100% water change with a quality salt, your water parameters should be near perfect.

This is quite easy to do on a 13.5gal tank. The problem with a 100% water change is with parameter stability. You don't want to correct things too fast.

I'd do 4 water changes over a week: day 1 = 30%, day 3 = 40%, day 5 = 50%, day 7 = 60%. This would change out over 90% of your water and correct your parameters to good enough.

Then track your consumption and dose appropriately.

I'd also measure your your salt mix to ensure your testing results are reasonable.

So the Salt I’m using is red seas coral pro which test at an alk of 11 whenever I’ve checked it freshly mixed, is going from 5.7 to 11 in a week not to sudden of a change?

arking_mark · Sep 26, 2021

ZipAdeeZoa said:
It definitely can although I forget the specifics of why it does, I should probably re familiarize with the cause of that, that may not be whats happening here buts its something I will for sure keep in mind

So the Salt I’m using is red seas coral pro which test at an alk of 11 whenever I’ve checked it freshly mixed, is going from 5.7 to 11 in a week not to sudden of a change?

The general conservative rule of thumb is 0.25 dKH per adjustment and a total of 1 dKH per day.

A 30% water change (4gal) with 11dKH water would raise your alk by 1.5. So I'd do;