Alk, calcium, magnesium. What’s next?

[Dine]

This is my first tank that I’ve really taken testing and tracking alk, calcium, and magnesium seriously on. Below is a graph of the last week and I’m looking to see what, if anything I should be doing or prepare to be doing.

25g tank
Water change 1/2g per day fritz rpm
Ph 7.9-8.0

currently 4 decent sized sps frags and 4 zoas. Planning on a mixed reef but more sps than anything. The declining Dkh, despite the daily water changes was a little surprising to me with so few corals

do nothing?
up the water changes?
Dose?
Don’t dose yet, but prepare?

just curious what more experienced reefers would be planning for at this point.

 

[gbroadbridge]

This is my first tank that I’ve really taken testing and tracking alk, calcium, and magnesium seriously on. Below is a graph of the last week and I’m looking to see what, if anything I should be doing or prepare to be doing.

25g tank
Water change 1/2g per day fritz rpm
Ph 7.9-8.0

currently 4 decent sized sps frags and 4 zoas. Planning on a mixed reef but more sps than anything. The declining Dkh, despite the daily water changes was a little surprising to me with so few corals

do nothing?
up the water changes?
Dose?
Don’t dose yet, but prepare?

just curious what more experienced reefers would be planning for at this point.

Honestly, I'd be doing nothing.

In fact, at that stage I'd be doing 10-15% water change every 2 weeks.

At least until I see a noticeable drop > 2 dkh in Alk.

 

[bakbay]

First - congrats! It’s very exciting and you can’t control your excitement, I know I couldn’t before! Ha

Second - relax, enjoy your tank and don’t chase numbers. 8.x dKh is fine - I seriously doubt that your frags are consuming huge amounts of Alk, likely coralline algae. How old is the tank?

Third - I would check N&P and make sure they don’t bottom out. What is your bio load / fish / feeding habits?

Finally - take a deep breath and not do anything drastic for now. Let your tank mature. Yes, you will likely need to dose later when you can’t keep up.

 

[Dine]

First - congrats! It’s very exciting and you can’t control your excitement, I know I couldn’t before! Ha

Second - relax, enjoy your tank and don’t chase numbers. 8.x dKh is fine - I seriously doubt that your frags are consuming huge amounts of Alk, likely coralline algae. How old is the tank?

Third - I would check N&P and make sure they don’t bottom out. What is your bio load / fish / feeding habits?

Finally - take a deep breath and not do anything drastic for now. Let your tank mature. Yes, you will likely need to dose later when you can’t keep up.

2 votes for do nothing is what I like to hear!

im holding nitrates around 8 pretty stable. Phosphate got out of control and as high as .3 but the daily water changes and reduced feeding have brought it down to .1. I expect next week I’ll be back to where I wanted to be and my hope is continuing the water changes will allow me to resume regular feeding.

1 Midas blenny
1 diamond watchman goby
3 snails
3 hermits
1 emerald crab

tanks about 4 months old so not mich coralline to speak of. Just a little on the snails but they were the first additions and it has remained on them since the beginning.

 

[bakbay]

2 votes for do nothing is what I like to hear!

im holding nitrates around 8 pretty stable. Phosphate got out of control and as high as .3 but the daily water changes and reduced feeding have brought it down to .1. I expect next week I’ll be back to where I wanted to be and my hope is continuing the water changes will allow me to resume regular feeding.

1 Midas blenny
1 diamond watchman goby
3 snails
3 hermits
1 emerald crab

tanks about 4 months old so not mich coralline to speak of. Just a little on the snails but they were the first additions and it has remained on them since the beginning.

Very nice - you’re on your way to a very cool mixed reef soon. I think maintaining Alk is the way to go. I try to keep mine at 8-8.5 myself but recently the Alk consumption has gone way up with higher pH (First Word problem). I’m upping the CaRx as we speak so hope it will settle in a few days…

 

[Dine]

Very nice - you’re on your way to a very cool mixed reef soon. I think maintaining Alk is the way to go. I try to keep mine at 8-8.5 myself but recently the Alk consumption has gone way up with higher pH (First Word problem). I’m upping the CaRx as we speak so hope it will settle in a few days…

I was struggling with relatively low PH. If you’re saying higher PH will result in more Dkh consumption thats more than likely explaining my increased consumption. I have added a skimmer (and am ready to attach a co2 scrubber to it if necessary) about a week ago. Bumped me from 7.6-7.8 to 7.9-8.0. I will likely experiment with the scrubber to see if I can break that 8.0 plane and stay there and leave everything else alone for now

 

[thatmanMIKEson]

I'm going to vote opposite, I would definitely start dosing 2part, especially since you have a monitor, it's super easy to start forcing a demand with a few ML a day it will let coraline start to grow faster. If your tank can take 5ml of alk and cal a week great! When you do this you will see the first week it starts to drop and you will need to start dosing to maintain dkh. In new tanks I will do this with just rocks, or even dripping kalkwasser is a great way to get the demand starting, the goal is to start a demand not sit on your hands. IMO...

 

[bakbay]

The OP is holding steady at 8.1 with the current demand of a few frags. So even if he dose from 8.1 to 9.x, the Alk consumption is the same right? I’m curious on what’s driving up “demand” here?

 

[Dine]

I'm going to vote opposite, I would definitely start dosing 2part, especially since you have a monitor, it's super easy to start forcing a demand with a few ML a day it will let coraline start to grow faster. If your tank can take 5ml of alk and cal a week great! When you do this you will see the first week it starts to drop and you will need to start dosing to maintain dkh. In new tanks I will do this with just rocks, or even dripping kalkwasser is a great way to get the demand starting, the goal is to start a demand not sit on your hands. IMO...

Ok 1 vote for 2 part. I will say my hope was to keep up with demand via AWC to replenish if possible but if I need to take additional steps that’s what I’ll do.

this is my first nano tank. I failed once with it, not prepared to deal with how sensitive they were to changes (evap killed me). This time I made this tank as stable as humanly possible with tech to monitor and track what’s going on. With my older tanks it was all by feel. But with this new found info I find myself wondering if I should react to the info or watch it longer. Double edged sword.

 

[Randy Holmes-Farley Verified Community Expert]

The OP is holding steady at 8.1 with the current demand of a few frags. So even if he dose from 8.1 to 9.x, the Alk consumption is the same right? I’m curious on what’s driving up “demand” here?

Higher alkalinity and higher pH both drive increased demand for alkalinity.

Alk and calcium demand is not a fixed value.

 

[Randy Holmes-Farley Verified Community Expert]

Ok 1 vote for 2 part. I will say my hope was to keep up with demand via AWC to replenish if possible but if I need to take additional steps that’s what I’ll do.

this is my first nano tank. I failed once with it, not prepared to deal with how sensitive they were to changes (evap killed me). This time I made this tank as stable as humanly possible with tech to monitor and track what’s going on. With my older tanks it was all by feel. But with this new found info I find myself wondering if I should react to the info or watch it longer. Double edged sword.

8 dKH is perfectly fine and I would not bother to dose anything until it drops more, unless you have a higher target value (I recommend 7-11 dKH).

It is always cheaper to maintain alkalinity and calcium by dosing than by water changes, unless you are going to do those same water changes for other reasons anyway.

Also, to maintain alk by water change, which only works with very low alk demand, you will need to be using a salt mix with alk substantially higher than your target level in the aquarium, otherwise it is a constantly losing battle unless you do very large water changes every day.

 

[Dine]

8 dKH is perfectly fine and I would not bother to dose anything until it drops more, unless you have a higher target value (I recommend 7-11 dKH).

It is always cheaper to maintain alkalinity and calcium by dosing than by water changes, unless you are going to do those same water changes for other reasons anyway.

Also, to maintain alk by water change, which only works with very low alk demand, you will need to be using a salt mix with alk substantially higher than your target level in the aquarium, otherwise it is a constantly losing battle unless you do very large water changes every day.

Got it. Makes sense. Currently I’m losing about 1dkh/week but will need another week to back that data up. I’ll monitor for a little while longer and come back with the results and another round of advice

 

[bakbay]

Higher alkalinity and higher pH both drive increased demand for alkalinity.

Alk and calcium demand is not a fixed value.

I believe that was the point I was making. I know that higher pH will drive demand for Alk. I’ve finally fixed the recirculating CO2 scrubber and drove pH past 8.4 (can clearly see the uptick).

I was saying that all else equal with no increase in coral mass or pH, dosing to get from 8.1 to 9.x does not contribute to a higher demand.

 

[Randy Holmes-Farley Verified Community Expert]

I was saying that all else equal with no increase in coral mass or pH, dosing to get from 8.1 to 9.x does not contribute to a higher demand.

Higher alk will typically result in higher alk demand.

 

[bakbay]

Higher alk will typically result in higher alk demand.

Ok - fair enough. You are absolutely right as always Sir. I was laser-focused on the OP’s tank with 4 frags.

 

[Dine]

So alk continues to fall (this is after a manual 20% WC) and .5g AWC continuing daily. At what point Dkh wise should I begin trying to keep it stable and stable to
What number.

 

[LobsterOfJustice]

I would start dosing 2-part to maintain alk around 8. If you’ve already got corals in the tank then you should start dosing to maintain levels. Don’t let it drop below 7. Make changes slowly. Staying at 7.2 is better than jumping to 8 instantly. Some people target different numbers and IMO it depends on your specific tank including lighting, nutrient levels, and other unknown factors, but usually 7-9 is safest.

 

[X-37B]

I would dose 2 part when you see dkh levels go down.
On a tank that size 10% a month WC works well for stability. No daily needed.
Pick your dkh level and focus on stability.
I run 7 on all systems. My range is 6.5-7.5. If out of that range I will adjust back to it.

In my old 20 I ran 2 part at an alk of 7. To keep it from going lower I hand dosed twice a day. Each dose brought the alk to a little over 8 and back to 7 in 12 hrs.
I was dosing once a day and the alk went to 9 then back to 7 in 24hrs. Never had an issue and ran this system for 8 months then took it down. Its now up again running a halide.
My 45 is dosed twice a day also by hand and does the same 7-8alk in 12hrs.
My 80 runs a carx.
The only issue with alk lower than 7 is the growth slows.