With 24 hr continuous water changes - what should I be dosing?

[Deej1534]

I’m running my Red Sea 900xxl on a 24-hour water change system using the Neptune DOS. I’m removing and adding around 1194 mL per hour sincBrightwell’system volume, with the sump in the basement, is closer to 265 gallons. That works out to roughly 20% a week.

I’m noticing I don’t really need to dose calcium and alkalinity much anymore. The constant water changes are replenishing the tank with fresh saltwater that has balanced KH and CA levels. I’m keeping an eye on this with my Trident and will keep monitoring to see if demand eventually outpaces what the salt can supply.

My question is about trace elements and magnesium. With water being cycled so often, I’m guessing those should stay pretty stable too. I’ll keep testing to confirm.

For those of you doing continuous or 24-hour water changes, what are you finding you still need to dose? Right now, I’m just planning to continue dosing Brightwell’s aminos and feeding coral food three times a day, and I’ll hold off on adding Part 1 & 2 until I see the tank really needs it again.

My real question here is - what are everyone's experiences with 24 hr water changes?

 

[KStatefan]

I dose Kalk, ammonia, and trace elements along with my AWC setup of 10% per week effective rate.

 

[Deej1534]

interesting so your continuing to dose your trace elements > have you run any tests to see what the consumption was?

Never dosed ammonia or talk - what's your experience? and how long have you been doing this?

 

[FishLvR]

I would LOOOOVE a automatic water change system. I just have no clue how I would pull it off because of where the tank is.

 

[KStatefan]

interesting so your continuing to dose your trace elements > have you run any tests to see what the consumption was?

Never dosed ammonia or talk - what's your experience? and how long have you been doing this?

I do an ICP MS test.

I have been dosing kalk since there was a demand and ammonia since i reset this tank.

 

[Deej1534]

What have you seen with dosing ammonia? How long have you been doing this for?

Kalk is something I keep saying I am going to dose but just haven’t bit the bullet yet. When I do it I am going to use one of the Kalk dosing chambers

 

[Randy Holmes-Farley Verified Community Expert]

IMO, AWC are great, and I change about 1% daily.

Unless the alk and calcium demand are quite low and the salt mix has higher alk than the tank, you will likely need to supplement alk and calcium (and magnesium) in some fashion. AFR is an easy, if expensive choice. If you have determined you do not need alk and calcium, you do not need magnesium (no matter what a kit says) and I wouldn't even measure it. It will be whatever your salt mix had.

I'd still look to dose trace elements in some fashion, such as AFR or Tropic Marin A and K.

 

[Deej1534]

IMO, AWC are great, and I change about 1% daily.

Unless the alk and calcium demand are quite low and the salt mix has higher alk than the tank, you will likely need to supplement alk and calcium (and magnesium) in some fashion. AFR is an easy, if expensive choice. If you have determined you do not need alk and calcium, you do not need magnesium (no matter what a kit says) and I wouldn't even measure it. It will be whatever your salt mix had.

I'd still look to dose trace elements in some fashion, such as AFR or Tropic Marin A and K.

Hmm interesting so even with new salt coming in daily you still recommend dosing trace elements? I am going to continue to watch the Kh and CA and see what happens. If I see it start to drop it’s easy to just start dosing and adjust the amounts. As of now it seems to be staying stable but that could change - what brand do you use for you CA and Kh?

 

[Randy Holmes-Farley Verified Community Expert]

Hmm interesting so even with new salt coming in daily you still recommend dosing trace elements? I am going to continue to watch the Kh and CA and see what happens. If I see it start to drop it’s easy to just start dosing and adjust the amounts. As of now it seems to be staying stable but that could change - what brand do you use for you CA and Kh?

Think of it this way:

Suppose you deplete all iron from the starting salt in a week or two. (not far off)

Then you replace 20% of that iron at the end of the week.

Soon, the only iron you have is starting at 20% of the salt value, and drops from there.

Water changes can never maintain the salt mix level unless you change 100% daily.

Of course, a big neglected source of trace elements are foods. Maybe much larger than water changes, but hard to quantify.

 

[Deej1534]

Hmm interesting so even with new salt coming in daily you still recommend dosing trace elements? I am going to continue to watch the Kh and CA and see what happens. If I see it start to drop it’s easy to just start dosing and adjust the amounts. As of now it seems to be staying stable but that could change - what brand do you use for you CA and Kh?

Think of it this way:

Suppose you deplete all iron from the starting salt in a week or two. (not far off)

Then you replace 20% of that iron at the end of the week.

Soon, the only iron you have is starting at 20% of the salt value, and drops from there.

Water changes can never maintain the salt mix level unless you change 100% daily.

Of course, a big neglected source of trace elements are foods. Maybe much larger than water changes, but hard to quantify.

This make total sense now are you dosing tropic Marin trace 1 & 2 for the trace elements? Also would you recommend sending water off once I start dosing?

I know my lfs has a few brands but I don’t know how good they are

 

[Randy Holmes-Farley Verified Community Expert]

This make total sense now are you dosing tropic Marin trace 1 & 2 for the trace elements? Also would you recommend sending water off once I start dosing?

I know my lfs has a few brands but I don’t know how good they are

I’m using AFR (which adds traces), and I also dose extra iron, manganese and iodide since my macroalgae is growing fast and likely using those up.

 

[Deej1534]

This make total sense now are you dosing tropic Marin trace 1 & 2 for the trace elements? Also would you recommend sending water off once I start dosing?

I know my lfs has a few brands but I don’t know how good they are

I’m using AFR (which adds traces), and I also dose extra iron, manganese and iodide since my macroalgae is growing fast and likely using those up.

I just order AFR and am going to start dosing next week when it arrives and I’ll keep on hand my pt1&pt2 to make slight adjustments. Anything I should know going into this? Will I see any swings in the tank or just dose for 265 gallons right off the bat and it should be a simple switch over?

 

[Randy Holmes-Farley Verified Community Expert]

I just order AFR and am going to start dosing next week when it arrives and I’ll keep on hand my pt1&pt2 to make slight adjustments. Anything I should know going into this? Will I see any swings in the tank or just dose for 265 gallons right off the bat and it should be a simple switch over?

Switch is simple, but note that you cannot detect the alk right away. Measure it later in the day or the next day just before dosing.

 

[Deej1534]

Okay sounds good - my trident runs 4 tests a day so I will just keep an eye on things for a little and increase as necessary

 

[rishma]

I feel like it takes longer to see all the alkalinity from the first dose. No data to back it up, since you have a trident it would be great if you came back here to share what you see. I think it takes +\- 24hrs for the first dose but less time for future doses.

The good news is that the alkalinity from AFR is predictable. Just match your current daily alkalinity consumption. For reference, 150ml of AFR will add 1 dKH in a 900L volume.

 

[Randy Holmes-Farley Verified Community Expert]

I feel like it takes longer to see all the alkalinity from the first dose. No data to back it up, since you have a trident it would be great if you came back here to share what you see. I think it takes +\- 24hrs for the first dose but less time for future doses.

The good news is that the alkalinity from AFR is predictable. Just match your current daily alkalinity consumption. For reference, 150ml of AFR will add 1 dKH in a 900L volume.

It’s very likely slow at first, but I agree I’ve not seen clear data to show that.

 

[bobnicaragua]

With 20% water change a week, I wouldn’t bother dosing trace elements. Especially with such low alk consumption.

 

[BryanM]

Okay sounds good - my trident runs 4 tests a day so I will just keep an eye on things for a little and increase as necessary

I have a KH Guardian that automatically tests alk and then doses, it was meant to dose sodium bicarbonate, but I found others in their FB support forums switched to AFR.

same thing, just had to keep an eye on alk, and adjust the dosage a bit - works very well.

 

[Reach4It]

I made this to sort out stuff.