Necessary Trace Elements for FOWLR?

[Marquarium]

One of my FOWLR tanks has still not needed a water change ever since I set it up ~4 months ago. Nitrates will not go above 18ppm and since this is a FOWLR I was going to start doing water changes once they hit 30. After all this time it still has still been in the 13-18ppm range.

I know for a reef tank I would need to be dosing trace elements that are depleted by the corals. But for a FOWLR what do I have to replenish if I am not doing water changes?

A LFS said I need to still be doing water changes to get trace elements the fish need. I've been thinking Seachem's Marine Trace for fish would've been enough though.
Reading online I've seen mixed things but most people don't seem to mention trace elements for fish.

QUESTIONS & DISCUSSION:
Should I be doing water changes on a FOWLR if the fish are all doing well and nitrates are not above 20?
Should I start doing water changes because if I don't down the line nitrates could become a problem? (Thinking of doing small 10% changes 2-4 times a month)
If I don't need to do water changes, what should I be dosing for fish?


Thanks!

 

[KrisReef]

Fish don't absorb much (any?) trace elements from the water. They get nutrition from digestion of food same as we do.
My wife loves magnesium in her bath tub but if she is low in mag she needs to either take a pill or put it in her diet. A well balanced diet is what is best and easiest.

 

[Louis Z]

Do you have cheatomorpha or a turf scrubber ?

 

[twentyleagues]

Water changes to keep the nutrients in the water at a low level and to keep the major 3 alk, calc and mag at a good level is all you need, unless running a fuge or ats. You dont need dosing as nothing is depleting any of the elements at a high rate like stoney corals would. It would not hurt to do monthly or biweekly water changes currently to help keep nitrate and phosphates at a good (which I would say are) level. Biological processing of ammonia to nitrite and nitrite to nitrate will consume some alk unless something is processing nitrate you will not get that alk back so some water changes will remove nitrate and replenish alk. Also there is the chance if lighting is strong enough you may start growing coralline algae which will use alk, calc and mag again water changes should be enough.

 

[Marquarium]

Do you have cheatomorpha or a turf scrubber ?

I do have a refugium with calupera so I keep the fuge light on 24/7


Good to see everyone has the same level of thinking I was having. Not super necessary to do the water changes for fish only since nitrates and phosphates aren't doing badly. But probably should still start doing some small ones.

Appreciate everyone's advice and thinking! My lights aren't super great on this tank so I'm probably not going to get coralline algae :(

 

[Louis Z]

The caulerpa may need the trace . Not knowing which one exactly . Iron is key to many algae. . Even with water changes and a FOWLR , I still need major elements added and trace due to the inverts in the tank .

 

[Boehmtown]

Largely stuffed Fowlr tanks can bleed out some essential traces and some sensitive fish like some tangs can get some issues. If your nitrates don't go above 18 I doubt your fish load is high enough to worry about, regardless I do regular water changes for all kind of preventative reasons

 

[Marquarium]

Largely stuffed Fowlr tanks can bleed out some essential traces and some sensitive fish like some tangs can get some issues. If your nitrates don't go above 18 I doubt your fish load is high enough to worry about, regardless I do regular water changes for all kind of preventative reasons

Nitrates today tested at 21ppm. Finally time to start doing some water changes :D

Also might start doing small doses on NO3PO4X. I'm paranoid now this is going to continue to climb too rapidly even with water changes because a week ago was at 18ppm.

 

[Boehmtown]

Fish can handle considerably more or no nitrates. The tank needs the nitrates. It seems like you're close to balanced. Id just continue with your plan. Do water changes when needed or when it's been too long.

 

[twentyleagues]

Nitrates today tested at 21ppm. Finally time to start doing some water changes :D

Also might start doing small doses on NO3PO4X. I'm paranoid now this is going to continue to climb too rapidly even with water changes because a week ago was at 18ppm.

I would not worry about n and p at any level for the fish. I would do nothing for those levels right now other than water changes. The water changes would be mostly to replenish calc, alk, yes they would remove some n and p too. What kind of caulerpa do you have and how much? You may need to give the caulerpa some iron and manganese but remember food you feed the fish will also add stuff like this so it will be more of a how healthy does the macro look and is it growing? My reef tank runs at around 30n and .09-.12p with caulerpa feather and grape and I need to harvest it every 2 weeks. Levels stay pretty steady week to week, for the first year they slowly rose until they leveled off. I do have a lot of corals that help as well and I do not think your macro alone will handle the bio load in time unless there is a lot of it and a lot of room for it to grow. I have not done a water change in I dont know how long to remove n or p. I did a 30g change (about 20%) to remove meds in august. I do dose afr but its a reef tank so I have to dose something. What kind of fish do you have? What size is the tank?

 

[Troylee]

Zero sense to dose trace in a fowlr… I mean I don’t even dose trace in my sps reef . Water changes and feeding fish supply plenty if you ask me.

 

[painter1982]

You can get an icp test done. That would show you what is needed instead of guessing.

 

[twentyleagues]

You can get an icp test done. That would show you what is needed instead of guessing.

Its not a reef tank I wouldnt worry about it. Fish dont need anything but saltwater and as long as you are doing something like water changes the little bit of what is in the saltwater that will be lost due to biological processes wont matter. Since they have a macro algae fuge some things like iron may become depleted, but you can tell that by how its growing. My guess is feeding the fish will add enough "trace" to keep it happy.

 

[painter1982]

You can get an icp test done. That would show you what is needed instead of guessing.

Its not a reef tank I wouldnt worry about it. Fish dont need anything but saltwater and as long as you are doing something like water changes the little bit of what is in the saltwater that will be lost due to biological processes wont matter. Since they have a macro algae fuge some things like iron may become depleted, but you can tell that by how its growing. My guess is feeding the fish will add enough "trace" to keep it happy.

Fish can survive like that. But if you want them to thrive and live a long and healthy life then they need close to natural seawater parameters too. That’s what they evolved to be in. The op was asking what to add. You wouldn’t want to guess what to add. You can overdose some and not have enough of another. An icp test is cheap insurance that would answer his question without doubt.

 

[Troylee]

Fish can survive like that. But if you want them to thrive and live a long and healthy life then they need close to natural seawater parameters too. That’s what they evolved to be in. The op was asking what to add. You wouldn’t want to guess what to add. You can overdose some and not have enough of another. An icp test is cheap insurance that would answer his question without doubt.

But yet we were keeping fish and corals 20 years before icp testing was a thang! I mean icp was a couple wrestlers turned rappers. “Insane clown posse”

 

[twentyleagues]

But yet we were keeping fish and corals 20 years before icp testing was a thang! I mean icp was a couple wrestlers turned rappers. “Insane clown posse”

I thought they were Rappers that tried wrestling and failed. Even though they are from my hometown I still dont know much about them. I used to see them at the local mall trolling the lot in their van......

 

[twentyleagues]

Fish can survive like that. But if you want them to thrive and live a long and healthy life then they need close to natural seawater parameters too. That’s what they evolved to be in. The op was asking what to add. You wouldn’t want to guess what to add. You can overdose some and not have enough of another. An icp test is cheap insurance that would answer his question without doubt.

ICP for fowlr not needed dosing also most likely not needed. ICP for reef tanks is debatable.

 

[painter1982]

Fish can survive like that. But if you want them to thrive and live a long and healthy life then they need close to natural seawater parameters too. That’s what they evolved to be in. The op was asking what to add. You wouldn’t want to guess what to add. You can overdose some and not have enough of another. An icp test is cheap insurance that would answer his question without doubt.

But yet we were keeping fish and corals 20 years before icp testing was a thang! I mean icp was a couple wrestlers turned rappers. “Insane clown posse”

How many twenty year old fish do you have? You definitely don’t need to do any tests to keep them alive. I bought my first saltwater fish 43 years ago it survived 7 years no test. But technology is better now. Might’ve lived10 years or more had we had testing back then.

 

[Troylee]

How many twenty year old fish do you have? You definitely don’t need to do any tests to keep them alive. I bought my first saltwater fish 43 years ago it survived 7 years no test. But technology is better now. Might’ve lived10 years or more had we had testing back then.

Let’s ask @Paul B how many icp test he’s done or how many trace elements he doses, his tank is 47 years old or something crazy like that! He’s got a pair of clowns over 20 years old if I remember correctly… haha! I don’t think he even changes water

 

[twentyleagues]

How many twenty year old fish do you have? You definitely don’t need to do any tests to keep them alive. I bought my first saltwater fish 43 years ago it survived 7 years no test. But technology is better now. Might’ve lived10 years or more had we had testing back then.

Fish dont use trace elements from the water. They get what they need from food. Yes its probably not great to have really high amounts of "bad" trace elements for some fish like copper, zinc and whatever, which is why I advocate doing water changes.