Water changes vs dosing trace elements

[JonasRoman]

I’m definitely far from having to worry about trace elements since I do 10% water changes every week and only have a handful of frags. But out of curiosity, when or if I need to worry about them would it be sufficient to just do 20% water changes every other day for a good 2 weeks whenever replenishment is necessary? I’d like to keep my tank simple and not have to worry about dosing trace elements in the future.

If you believe its important to have all traces like in natural sea water ( I do not) then theoreticaly "only" water chenges can never fully replace consumption, it just replace exactly those % you change. Lest say that Lithium is consumed from its original value "1.0" to "0.5" between your water changes, and you replace 20% with new water with Lithium conc "1.0" then the new concentration after water change is: "0.6". Now this 0.6 is consumed in same speed, then its 0.1 after same period, and now you again do your 20% water change, now you have Lithium of 0.36. So the WC prevents from being totally depleted but can never restore to NSW levels. So the questions is rather:" Do we believe its important to have all traces closed to NSW? If we do, you must spot dose all based on ICP. Me personaly do not believe all traces are important, because just becasue they exists doesnt mean coral need it. The only thing we really know is that its toxic in too high levels. SO, for me your way is the best, that keeps traces never toxic levels, never zero, but always below NSW, which I do not believe is any issue at all. Its also easy, and reasonable cheap, and most important, safe.

/Jonas

 

[AlexandraDreadlocksPanda]

I’m definitely far from having to worry about trace elements since I do 10% water changes every week and only have a handful of frags. But out of curiosity, when or if I need to worry about them would it be sufficient to just do 20% water changes every other day for a good 2 weeks whenever replenishment is necessary? I’d like to keep my tank simple and not have to worry about dosing trace elements in the future.

Who has the time to do a 20% water change every 2 days? The trick to having a healthy reef in the long term is building sustainable routines. Make it easier on yourself to keep up the chores and they’re more likely to be done consistently.
On my 680L system I aim for 40% per month WC, doesn’t always happen if work commitments or time away interfere, but most of the time it’s a combo of 10% weekly / 20% fortnightly.
I also dose Tropic Marin elements A- & K+, they get added to my Randy’s recipe 2 part. I mix up 20L of each at a time then add a litre bottle of A- or K+ to their relevant ones.

KISSES: Keep it simple, stable, easily sustainable….

 

[breathing underwater]

I've always been surprised how so many reefers say that water changes are enough for trace element replenishment. Maybe that could be true for fish only, or maybe softies and LPS, (because maybe they don't need them?), but I'm convinced that for SPS (which is all I've had for many years) water changes won't suffice. As Randy alluded to, if you perform a 10% water change, you are only replacing the lost trace elements in 10% of the water.

I have a fairly elaborate system for adding trace elements every day, and I tweak the amounts every few months with ICP. If I didn't supplement them, my levels would drop to dangerously low levels (for SPS).

In recent years, I stopped water changes and just depended on ICP and supplementation but recently, with the introduction of the Oceamo Organo-MS test, I found that I had a very high level of plasticizers. This reminded me that the reason for water changes is not only to replenish trace elements but also to get rid of harmful compounds that accumulate. Some of these compounds can be tested for, but who knows how many others cannot be.
(I will soon post a thread on my "plasticizers experience," what I think might be the culprit, and what I am doing about it).

I'm all for people enjoying experimenting and seeking more perfect water quality or coral health with trace elements, but can definitely say small regular water changes along with other inputs like fish food like @Randy Holmes-Farley mentioned CAN grow SPS, and in great density. I for years ran my 70 gallon 24x36 SPS reef with plain BRS two part, water changes of 5 gallons (~8%) per week on most weeks, and saw great growth and color:

This was the central blue stag when I took the tank down to move to a new house!

In my experience, the critical challenge was pushing enough calculator and alkalinity through the system for such density while keeping things stable. Any dosing pump hiccups can be very disruptive!
On a related side note my new tank, I am planning on running both two-part and All4Reef in tandem for redundancy and to halve the salinity creep. But so far it's small frags so I am just doing the All4Reef and adding Alk or Calc as adjustments as needed. I'm planning to layer in the two-part more later when demand calls for it.
Anyway sorry I guess I'm off on a tangent. Regular water changes and macro dosing of major elements CAN certainly grow SPS!! I'd say stability is more important than perfection.

 

[rishma]

I'm all for people enjoying experimenting and seeking more perfect water quality or coral health with trace elements, but can definitely say small regular water changes along with other inputs like fish food like @Randy Holmes-Farley mentioned CAN grow SPS, and in great density. I for years ran my 70 gallon 24x36 SPS reef with plain BRS two part, water changes of 5 gallons (~8%) per week on most weeks, and saw great growth and color:

This was the central blue stag when I took the tank down to move to a new house!

In my experience, the critical challenge was pushing enough calculator and alkalinity through the system for such density while keeping things stable. Any dosing pump hiccups can be very disruptive!
On a related side note my new tank, I am planning on running both two-part and All4Reef in tandem for redundancy and to halve the salinity creep. But so far it's small frags so I am just doing the All4Reef and adding Alk or Calc as adjustments as needed. I'm planning to layer in the two-part more later when demand calls for it.
Anyway sorry I guess I'm off on a tangent. Regular water changes and macro dosing of major elements CAN certainly grow SPS!! I'd say stability is more important than perfection.

Nice tank and the method you describe was essentially what i did for many years. I had never heard of ICP for the first 25!years of my reefing.

Why not sure part C with your 2 part to avoid the salinity creep? You can dump trace in your 2 part and have the best of all worlds. If I wasn’t using kalk and AFR, I’d use 2part+C with trace mixed in.

 

[breathing underwater]

Nice tank and the method you describe was essentially what i did for many years. I had never heard of ICP for the first 25!years of my reefing.

Why not sure part C with your 2 part to avoid the salinity creep? You can dump trace in your 2 part and have the best of all worlds. If I wasn’t using kalk and AFR, I’d use 2part+C with trace mixed in.

Yes it would probably be an improvement to add trace either as a part C or added within the two part elements. From my understanding salinity creep remains an issue for all two-part systems as the excess sodium and chloride ions from the respective parts is continually being added as more calcium and carbonate are consumed and therefore accumulates as additional salinity. Trace or not doesn't change that aspect of the two part design.

On my reef that usually amounted to about a gallon of freshwater dilution needed each week. Not a big deal by any means as I just did that during regular water changes, though when taking long trips for three weeks or more with no water changes or dilution, the effect became noticeable so I would lower my salinity to about 34 ppt before leaving. Otherwise I'd be trending toward a red sea biotope!
As I noted this time around I am using AFR and the lack of salinity creep is nice. But my demand is so far not that intense so not really an issue either way for now.

 

[rishma]

Yes it would probably be an improvement to add trace either as a part C or added within the two part elements. From my understanding salinity creep remains an issue for all two-part systems as the excess sodium and chloride ions from the respective parts is continually being added as more calcium and carbonate are consumed and therefore accumulates as additional salinity. Trace or not doesn't change that aspect of the two part design.

On my reef that usually amounted to about a gallon of freshwater dilution needed each week. Not a big deal by any means as I just did that during regular water changes, though when taking long trips for three weeks or more with no water changes or dilution, the effect became noticeable so I would lower my salinity to about 34 ppt before leaving. Otherwise I'd be trending toward a red sea biotope!
As I noted this time around I am using AFR and the lack of salinity creep is nice. But my demand is so far not that intense so not really an issue either way for now.

Part C (sold by Tropic Marin, other brands have it too) is a sodium free salt. It is added to balance out the excess sodium from 2 part and ensure ions stay in balance. It prevents salinity creep.

 

[rishma]

@breathing underwater see the first post of this thread

DIY Balling Method Recipe

The Balling DIY supplement recipe utilize a 1:1:1 dosing ratio to maintain proper alkalinity. For instance, if you require 50 mL of the alkalinity solution, you should also add 50 mL of Calcium and Balling. Alkalinity (Choose One) : Option 1: Soda Ash Add 375 g soda ash to enough RO/DI to...

www.reef2reef.com

 

[breathing underwater]

Part C (sold by Tropic Marin, other brands have it too) is a sodium free salt. It is added to balance out the excess sodium from 2 part and ensure ions stay in balance. It prevents salinity creep.

You still need to take OUT the excess sodium chloride from parts A and B though. You could probably program a doser to dump a small amount of tank water each day and then your top off would take care of it, if you were seeking a hands off solution.

I dunno, maybe @Randy Holmes-Farley can clarify it if I'm mistaken but I believe this is an inherent feature of two part dosing. No NaCl salt is basically a very broad spectrum trace solution, not a means of removing excess ions but rather rebalancing ions.

 

[rishma]

@breathing underwater
You are correct in that I said salinity drift, which will still go up if you don’t change water. Part C maintains the ion balance so the saltwater still has the same sodium, magnesium, potassium, sulfates, etc as normal seawater. Without it, you get sodium increasing while the others do not and it gets out of balance. Na free salt should not be used as a trace element solution IMO, though some advertising implies that it is which leads to lots of misunderstanding. It simply adds the other non-sodium components of saltwater like magnesium chloride, potassium chloride, sulfates, etc so saltwater stays normal saltwater.

You are correct though, it would be adding saltwater to your saltwater tank and salinity will go up. It just goes up in a balanced way.

 

[breathing underwater]

@breathing underwater
You are correct in that I said salinity drift, which will still go up if you don’t change water. Part C maintains the ion balance so the saltwater still has the same sodium, magnesium, potassium, sulfates, etc as normal seawater. Without it, you get sodium increasing while the others do not and it gets out of balance. Na free salt should not be used as a trace element solution IMO, though some advertising implies that it is which leads to lots of misunderstanding. It simply adds the other non-sodium components of saltwater like magnesium chloride, potassium chloride, sulfates, etc so saltwater stays normal saltwater.

You are correct though, it would be adding saltwater to your saltwater tank and salinity will go up. It just goes up in a balanced way.

Yeah cool, I figured we were talking about the same thing just from different directions. I could see how you could go about using that and an automatic or manual water discharge to keep everything in balance without water changes. Personally I haven't tried that yet, and currently am trying out AFR as an alternative to try something new to me.

Happy reefing!

 

[rishma]

@breathing underwater
You are correct in that I said salinity drift, which will still go up if you don’t change water. Part C maintains the ion balance so the saltwater still has the same sodium, magnesium, potassium, sulfates, etc as normal seawater. Without it, you get sodium increasing while the others do not and it gets out of balance. Na free salt should not be used as a trace element solution IMO, though some advertising implies that it is which leads to lots of misunderstanding. It simply adds the other non-sodium components of saltwater like magnesium chloride, potassium chloride, sulfates, etc so saltwater stays normal saltwater.

You are correct though, it would be adding saltwater to your saltwater tank and salinity will go up. It just goes up in a balanced way.

Yeah cool, I figured we were talking about the same thing just from different directions. I could see how you could go about using that and an automatic or manual water discharge to keep everything in balance without water changes. Personally I haven't tried that yet, and currently am trying out AFR as an alternative to try something new to me.

Happy reefing!

Yep, slightly dilute AWC and good to go!

I currently use AFR. Best new product of the last decade IMO.

 

[Randy Holmes-Farley]

If I were to use a two part, I'd definitely use an ion-balanced method that either had something like TM Part C or had those same ions built into the other parts (like ESV does).

It's not just trace elements,. It also keeps major and minor ions from depleting due to the required salinity corrections, such as potassium, bromide, etc.

 

[JonasRoman]

This subject is actually also another one: Do we need to have all traces in exact same conc as in natural sea water (NSW)? I would say no, and that is definitely sustained by own experience. I have never chased all elements, and only spot dose Sr, I, and sometimes also F.
You can say "X is needed as coofactor in enzymes etc, and therefore we must have same as NSW. " How do we know that the enzymatic function doesnt work if surrounding water has 50% of the NSW value of X? The concentration in water is just reflecting that we havent used up all, and I do not think that coral can't manage take up a traces just because its lest say 30% of its NSW concentration. So with this said: Ofcourse just a WC will only replace that % that you change, so oufcourse WC is never enough IF you want to replenish traces back to NSW levels. BUT, as we see that this regim works in many cases, its just tells us that its not that important. Obviously not, as there is so many tanks out there with thriving demandning corals, that definitely not have all the traces as in NSW. This is a business that arised when ICP was coming to the hobby. For me, as I have said before ICP is mostly to see that I havent too much of any poisoning traces, because that we at least know, is not good.

And to clarify, I do not say the traces is not needed, they are, but I do not think its crucial to aim at exact same values as in NSW as long as we are above 0=we have not depleted the element totally. So my own strategy has always been to combine WC and Alk/Ca dosing recipes with traces. That prevent traces to go to zero, but will not replenish fully up to NSW.


/Jonas

 

[Randy Holmes-Farley]

This subject is actually also another one: Do we need to have all traces in exact same conc as in natural sea water (NSW)? I would say no, and that is definitely sustained by own experience. I have never chased all elements, and only spot dose Sr, I, and sometimes also F.
You can say "X is needed as coofactor in enzymes etc, and therefore we must have same as NSW. " How do we know that the enzymatic function doesnt work if surrounding water has 50% of the NSW value of X? The concentration in water is just reflecting that we havent used up all, and I do not think that coral can't manage take up a traces just because its lest say 30% of its NSW concentration. So with this said: Ofcourse just a WC will only replace that % that you change, so oufcourse WC is never enough IF you want to replenish traces back to NSW levels. BUT, as we see that this regim works in many cases, its just tells us that its not that important. Obviously not, as there is so many tanks out there with thriving demandning corals, that definitely not have all the traces as in NSW. This is a business that arised when ICP was coming to the hobby. For me, as I have said before ICP is mostly to see that I havent too much of any poisoning traces, because that we at least know, is not good.

And to clarify, I do not say the traces is not needed, they are, but I do not think its crucial to aim at exact same values as in NSW as long as we are above 0=we have not depleted the element totally. So my own strategy has always been to combine WC and Alk/Ca dosing recipes with traces. That prevent traces to go to zero, but will not replenish fully up to NSW.


/Jonas

I agree that we have little good info on trace element levels needed, and concentration alone would not tell us anyway since there are many different chemical forms, especially considering organic binding to all sorts of different organics in the water.

 

[JonasRoman]

I agree that we have little good info on trace element levels needed, and concentration alone would not tell us anyway since there are many different chemical forms, especially considering organic binding to all sorts of different organics in the water.

Do you know if there exists an unbuased review of what we know today concerning this? We cant ask ICP company nor company that sell traces (sometimes same), but would like to know if there are true studies? I have seen a few concerning a specific trace element. Maybe someone can do a summary of what we know today, and then we update that.

Wish you all good 2026 reef year:-)

Jonas

 

[Randy Holmes-Farley]

Do you know if there exists an unbuased review of what we know today concerning this? We cant ask ICP company nor company that sell traces (sometimes same), but would like to know if there are true studies? I have seen a few concerning a specific trace element. Maybe someone can do a summary of what we know today, and then we update that.

Wish you all good 2026 reef year:-)

Jonas

I’ve not seen such a summary.

 

[WhatCouldGoWrong71]

I do trace, CARX/Kalk annd anmmonia/ureah. And, I feed 12 times a day, 6 frozen 6 dry. I’m AWC plus I do 5g a week of a slow wet skim. Display is 14 months old. I had a 100g tank that went into this 400g display, but added a ton. I do ICP every 3 weeks. I hate to change things, but I have been slowly unwinding things. Next to go is aminos. With all I feed, I should be covered. I went over board with lighting and flow, which I think are my key drivers.

I often wonder about trace and the salt we use. I know for a fact I am consuming a ton of trace that my salt is not replenishing to the levels I am aiming for (clearly not set by me). I use blue Fritz. I have been tempted to make a switch to a high end/premium salt, but, is it worth it in the long run? More expensive water that I flush 8 -10 gallons a day or trace.



But - I really don’t mind that I don’t have to clean my bins often at all though. It’s a besr to unhook my 300g bins.