Yet another water change question…

[TeeSquared1214]

So I started my reefing journey back in maybe August of last year. I’ve been pretty good about testing my nutrients and dosing what was needed etc and of course had a couple of mishaps where Alk or other nutrients were lower than what they should’ve been. However, despite my levels being pretty consistent for the past few weeks. Corals that I was expecting to see growth on, or anything in my tank except for bubble algae and sea lettuce have been growing. Those aren’t growing terribly fast either.

All of this to say, I’ve only done a water change once. And even then it was maybe 10 gallons in my 100 gallon display + 50ish gallon sump.

Given the lack of growth over the past few months. Should I be doing more water changes to supply coral with trace elements?

The only things I’ve dosed have been Red Sea ABC foundation for Calcium, Alk, and Magnesium. I occasionally dose aminos, I feed reef roids about 1-2 times a week, depending on phosphate levels, and have only dosed all for reef a times.

My suspicion is now trace elements.

Here are my parameters along with the dates for the past few times I tested:

—3/14/2025–

Salinity - 1.025

Alkalinity - 8.3dKH

Magnesium - 1405ppm

Calcium - 465ppm

Phosphate - 0.04ppm

PH - ~8

Nitrate - 7.3ppm

Nitrite - 0ppm

Ammonia - 0ppm



—3/21/2025–

Salinity - 1.026

Alkalinity - 7.6dKH

Magnesium - 1460ppm

Calcium - 490ppm

PH - ~7.8



—3/27/2025–

Salinity - 1.026

Calcium - 475ppm

Alkalinity - 8.4dKH

Magnesium - 1400ppm

Phosphate - 0.11pp

Nitrate - 9.2ppm



—4/2/2025–

Salinity - 1.026

Alkalinity - 7.6dKH

Phosphate - 0.03ppm

Magnesium - 1380ppm

Calcium - 455ppm

PH - ~8

 

[bluemon]

It’s a loaded question since we don’t know your other setup like lighting.

Definitely do a water change.

One water change in almost a year is…. Not ideal. Surprised the corals haven’t died.

Aim for at least one WC a month if you are comfortable with parameters, but 10% a week is ideal.

Trace elements are probably all drained and only a water change can supply those now.

Also, if you want more growth, might want to look into raising the alk a bit to 9ish as that will promote growth and your nutrients can handle it.

 

[TeeSquared1214]

It’s a loaded question since we don’t know your other setup like lighting.

Definitely do a water change.

One water change in almost a year is…. Not ideal. Surprised the corals haven’t died.

Aim for at least one WC a month if you are comfortable with parameters, but 10% a week is ideal.

Trace elements are probably all drained and only a water change can supply those now.

Also, if you want more growth, might want to look into raising the alk a bit to 9ish as that will promote growth and your nutrients can handle it.

Everything else is on PAR (pun intended). Such as lighting and flow. I rented a par meter a while back and made sure to map out my tank, so I don’t believe that’s the issue. But yeah, I’ve constantly felt like I was doing something wrong with no (one) water changes, but I always see how loaded of a question it is given that some people never do water changes and some swear by them. I’m currently mixing some saltwater now and looking to do a 10% water change here shortly. I’ll definitely look into raising alk as well. I’ll measure after my water change to ensure I don’t over or under do it.

 

[WhatCouldGoWrong71]

You don’t mention what type of coral you have in the tank. So, some of my answer(s) would depend on that. For example, if you have only leathers, GSP, BTs and Zoas, etc vs SPS/LPS, way different model. And then I would also have some questions for you if it were an SPS dom tank.

Me - I believe in 10% water changes weekly no matter what. But, I never had a softy only tank. Also, if it was SPS, if you have 5 frags would be different then 35.

 

[bluemon]

Everything else is on PAR (pun intended). Such as lighting and flow. I rented a par meter a while back and made sure to map out my tank, so I don’t believe that’s the issue. But yeah, I’ve constantly felt like I was doing something wrong with no (one) water changes, but I always see how loaded of a question it is given that some people never do water changes and some swear by them. I’m currently mixing some saltwater now and looking to do a 10% water change here shortly. I’ll definitely look into raising alk as well. I’ll measure after my water change to ensure I don’t over or under do it.

Since you have done 1 10% change in almost a year, I would just do a 25-30% change. And remember to raise alk very slowly

 

[TeeSquared1214]

You don’t mention what type of coral you have in the tank. So, some of my answer(s) would depend on that. For example, if you have only leathers, GSP, BTs and Zoas, etc vs SPS/LPS, way different model. And then I would also have some questions for you if it were an SPS dom tank.

Me - I believe in 10% water changes weekly no matter what. But, I never had a softy only tank. Also, if it was SPS, if you have 5 frags would be different then 35.

Good points. It’s ideally supposed to be a mixed reef, but id say it’s 50/50 softies and LPS. I had a monti, but lost it last month due to my tank issues.

GSP on back wall.
Candy Corn Chalice
Assorted Zoas for Zoa Garden
Devils Hand Leather
Pink Cabbage Leather
Rainbow Bubble Tip Nem
Branching Frogspawn
Cool Runnings Favia
Tye Dye Acan Echinata
Kenya Tree
Orange Jawbreaker Mushroom
Miami Micromussa Lord
Random Paly

 

[TeeSquared1214]

Good points. It’s ideally supposed to be a mixed reef, but id say it’s 50/50 softies and LPS. I had a monti, but lost it last month due to my tank issues.

GSP on back wall.
Candy Corn Chalice
Assorted Zoas for Zoa Garden
Devils Hand Leather
Pink Cabbage Leather
Rainbow Bubble Tip Nem
Branching Frogspawn
Cool Runnings Favia
Tye Dye Acan Echinata
Kenya Tree
Orange Jawbreaker Mushroom
Miami Micromussa Lord
Random Paly

About 8 different zoas to be more specific.

 

[bluemon]

Good points. It’s ideally supposed to be a mixed reef, but id say it’s 50/50 softies and LPS. I had a monti, but lost it last month due to my tank issues.

GSP on back wall.
Candy Corn Chalice
Assorted Zoas for Zoa Garden
Devils Hand Leather
Pink Cabbage Leather
Rainbow Bubble Tip Nem
Branching Frogspawn
Cool Runnings Favia
Tye Dye Acan Echinata
Kenya Tree
Orange Jawbreaker Mushroom
Miami Micromussa Lord
Random Paly

If you aren’t seeing growth with these softies, definitely a red flag. And something that trace elements in a water change will help with. I think one main think you must be depleted on are Iodine

 

[TeeSquared1214]

If you aren’t seeing growth with these softies, definitely a red flag. And something that trace elements in a water change will help with. I think one main think you must be depleted on are Iodine

Growth has been minimal over the past couple months, but not halted, just really really slow compared to earlier on.

 

[Pod_01]

Just couple of comments, water change will only replace portion of trace elements. If you do 10% water change it will only increase trace elements by 10%. Water change is not the best option to replace trace elements.

Corals do require certain essential trace elements to grown. My suggestion would be to try Tropic Marine A and K trace elements and see if things improve. I would use the minimum recommended dose.
I use TM A and K and corals look happy:

Alternatively you could switch to TM AFR, it contains Alk, Calcium, Mg and TM A and K elements. Real simple solution.

Next I find corals do best for me when I keep PO4 above 0.1ppm. Rapidly sinking PO4 is usually not a good sign especially when below the 0.1 ppm.
Some reefers make it work in the sub 0.1ppm range but it never worked out for me.

Good luck,

 

[TeeSquared1214]

Just couple of comments, water change will only replace portion of trace elements. If you do 10% water change it will only increase trace elements by 10%. Water change is not the best option to replace trace elements.

Corals do require certain essential trace elements to grown. My suggestion would be to try Tropic Marine A and K trace elements and see if things improve. I would use the minimum recommended dose.
I use TM A and K and corals look happy:

Alternatively you could switch to TM AFR, it contains Alk, Calcium, Mg and TM A and K elements. Real simple solution.

Next I find corals do best for me when I keep PO4 above 0.1ppm. Rapidly sinking PO4 is usually not a good sign especially when below the 0.1 ppm.
Some reefers make it work in the sub 0.1ppm range but it never worked out for me.

Good luck,

So simple question then because of just how new I am. But what if any point would a water change provide if trace elements are just dosed?

Just curious, and yeah I’m working on the phosphate management part. My nitrates and phosphates have typically been 0 except the past month or two. So I’m getting the hang of it slowly but surely.

 

[Pod_01]

So simple question then because of just how new I am. But what if any point would a water change provide if trace elements are just dosed?

Just curious, and yeah I’m working on the phosphate management part. My nitrates and phosphates have typically been 0 except the past month or two. So I’m getting the hang of it slowly but surely.

Water change can reduce things like organics, NO3 etc… that can accumulate. Water change can correct some water chemistry issues like elevated calcium etc… caused by unbalanced 2/3 part system.

Here is guide I follow that really improved my corals:

Good luck,

 

[Gumbies R Us]

So simple question then because of just how new I am. But what if any point would a water change provide if trace elements are just dosed?

Just curious, and yeah I’m working on the phosphate management part. My nitrates and phosphates have typically been 0 except the past month or two. So I’m getting the hang of it slowly but surely.

You could dose AFR (All for Reef) if you wanted to. This does contain some trace elements and would keep both your alk and calcium stable

 

[TeeSquared1214]

You could dose AFR (All for Reef) if you wanted to. This does contain some trace elements and would keep both your alk and calcium stable

I was worried about doing this as my Alk and Calcium were already fine. But I suppose in place of the red sea ones I could do this. For a a few weeks I was only dosing alk so unsure how that would work in that scenario.

 

[DrkNMighty]

I was worried about doing this as my Alk and Calcium were already fine. But I suppose in place of the red sea ones I could do this. For a a few weeks I was only dosing alk so unsure how that would work in that scenario.

If you wanted to keep dosing what you are you could add in something like Tropic Marin A and K. That is supposed to supplement trace elements and is what I’m currently looking at as all my trace elements were low based on ICP test. Red Sea also makes a trace element dosing product.