New to FOWLR - need much info


New member

I have been keeping salt water tanks for verious complexity since 1980. Now i have never kept a FOWLR, but have had very large successful reef systems.

I am thinking about setting up a large tank, 180 gal or more, for FOWLR. So I have a lot of questions.

1. Can someone direct me to a source of info on these setups.

the rest are specific questions:

2. What lighting is best, or acceptable for FOWLR. I would assume I want to drive some coraline algae, and of course keep the live rock 'alive'. But don't want algae problems (maybe the fish population takes care of that?)
3. filtration: Eg, sand bed?, lbs of live rock per gal, what types of additional filtration is necessary?
4. do I need to dose, or keep calcium up etc.
5. Skimmer (I would assume this is most important in a heavy fish loaded tank).

Anything else I have missed?

so here is my thought and if I am completely mistaken please correct me. I am thinking this might be less expensive and less difficult than a reef. But as i walk through the questions, I am thinking maybe I am mistaken. Please advise.



New member
Go as big as you can with FOWLR's because there are soooo many nice fish you will end up wanting! If you have kept successful reefs in the past and for so long, you should have no problems with FOWLR. Try to keep the set up the same as you would with a reef but minus things like a calcium reactor (unless you have one and want to use it). I find people sometimes think FOWLR tanks do not need the same water quality as a reef because of the lack of corals but I disagree. Fish deserve under 5 nitrates too in my opinion!

2. I went with T5's on my FOWLR this time and love them. I have "planted" my tank though with lots of macro algae and some mushrooms, so I needed decent light. I would always get good lighting though anyways for a FOWLR...Your buying beautiful fish, you should be able to see them properly and lighting really makes a tank look good...or bad. My last FOWLR had halides, simply because I love the look. No algae problems.

3. I like a shallow sand bed for FOWLR's myself but it depends on the system. LR...I personally have 200 lbs. in my 130G but most of it is in my sump and refugium which are both 50G. I would also add ozone if you feel comfortable running it. Its quite easy and really keeps your water quality nice. Make the water crystal clear too :)

Oh and I only have to clean my glass once in a while when I run ozone...without, it was every few days or so.

4. I dose calcium. For one, I have Halimeda macro algae which needs it but also because I have lots of coraline growth that I want to keep going. I also dose trace elements and iron for my macro algae.

5. Yes...Go with a big overrated skimmer!

I think it is less difficult than a reef for sure BUT don't neglect husbandry. Its not less work than a reef in my opinion. And you can't really leave out a bunch of equipment. It is less expensive though because your buying $60 sticks :)

Good luck!


New member

What the concerns/risks of running ozone. What is the method in a FOWLR tank, and what exactly is happening that helps prevent algae?

If id did go with halides, I assume 150 WATT units over a 180 gal would be okay?

Also, can I get by without a sump? Maybe a hang on the back refugium(s), such as CPR Aquaflows, and maybe a very good HOB Skimmer?

Is it absolutely necessary to us RO water (a big expense and a pain in the reef systems).


New member
Yes fish tanks are a little easier to maintain then reefs but not neccessarily less expensive. Fish can run you anywhere from $6-$2000 so it can get a bit pricey.

All of jpsmiths ideas are good ones. Shallow sand bed(I use crushed coral because the fish will always be messing around in there and creating sand storms with anything smaller), dose calcium and a big skimmer.

Ozone is primarily to kill parasites in the water but it also kills plankton, pods and algae so sometimes it can be a bad thing too. I don't use one but I qt for a month any fish I buy so I never have or had parasites in the main tank.

150watt hqi I would say would be perfect if you want halides. If you want a little less expensive you can use just pc lighting which you can ebay real cheap. It's perfect for keeping live rock going.

Sumps are alot of help especially for keeping a large fuge which I find essential to keeping any kind of saltwater tank. Really knocks the phosphates and nitrates down while feeding critters to the tank. I think you could get a hob fuge but I would make as large a one as you can fit on the aquarium. It will have to be cleaned out pretty regularly though.

Another thing to check is fish aggression and compatibility. Some of these fish can get real nasty. So you have to pick fish mates wisely or you could up with an expensive dead fish. I always add my new fish in 3's. This spreads out the aggression immensely. If you just add one at a time that one fish will take a serious pounding from everybody. Of course your qt tank has to be able to handle 3 fish at a time. I use a 20g and it seems to work but I always keep it going with a chromis in it.

What ever you do keep us posted to see the progress. Good luck!


New member
I agree with Sean about QTing and adding fish in threes. I often do it in twos but generally with aggressive fish, you want a few going in to avoid too much stress.

As for ozone, it can be a little tricky. You can run it through your skimmer but it can slowly degrade the skimmer. I do not like running it this way because I have a very expensive skimmer. A lot of people run it though a separate older or cheap skimmer. I just built a PVC reactor for mine.

Ozone will only kill pods that get into the reactor or skimmer though, so if you have a refugium, it does not effect them. I have a crazy amount of pods in my tank. Ozone does help keep parasites to a minimum but mostly keeps water quality so good that fish immune system is not affected by parasites. It breaks down ammonia and nitrites before they are even detectable.

Read these if you are thinking of ozone...lots to read but you will learn all you need:

If you want a big skimmer, you need a sump. There is no effective skimmer for a 180G FOWLR that is HOB. It sounds like you want a nice clean algae free tank with lots of nice fish...sump is a must! Its also the only way to keep a big refugium :) I also agree with Sean when he said a refugium is a must for any saltwater set ups...It certainly is for me because I hate hair algae...

You can go with rubbermaid containers like I did or get a pre made sump but just keep it simple. I think without one though, your only going to get frustrated.

Hope this helps some more!


New member
What about use of RO water for top offs, is it necessary to use RO water, or can i get by with just tap? Also, what about water changes, can I mix with just tap water?


New member
You can use tap water for sure but it will most likely cause algae problems like in any saltwater tank. I use RO/DI myself...I really dislike too much hair algae!


New member
Not really in my experience but maybe I just had the wrong ones. Mine really were not interested in the bad types of algae but did like the kinds I wanted in the tank! I did have a Kole Tang that ate hair algae all day long but I would have needed 12 of them to really make it disappear...and I did not really have a bad hair algae problem! I would not rely on tangs to keep bad algae in check. I seriously would set this tank up with a nice skimmer, RO water, phosban reactors, ect. Like a reef. Its not worth buying all these nice fish and then not enjoying them because your frustrated with all the algae. I know from experience.

Water Box

New member
I would definately agree with the advice about a good skimmer. The bigger the tank=the more fish you might add=the bigger skimmer you will need.:)
So a sump and skimmer are pretty important to me. As a matter of fact I only run a skimmer, live rock, and use alot of water flow.
Every so often I will run a large bag of carbon or other media if necessary so a little extra room in the sump doesn't hurt.
Currently I am only using enough substrate just to cover the glass.
I have used tap water for years and have had good luck and bad (mostly bad), recently I picked up a bigger RO/DI so I am contemplating using RO water.
Anyway $.02 cents inserted and good luck!


New member
I have used tap water for years with no problems. I use amquel+ and novaqua+ to take out cloramines and metals. I believe that my fuge is so large it takes out alot of the phosphates and nitrates in the tap water. I had a ro/do unit but had trouble with the float switch and it kept staying on all night(like 3 times) so I don't use it anymore. It is still hanging on the wall in my basement though.


New member
It will be 20g when I do them. The tank has been set up for only 2 months since the transfer from my 55g which was set up for 4 years. I only did water changes every 2 months or so on my 50g and it will probably be less on this tank. Maybe every 3 months. I also had a gravity fed fuge on my 55g so my nitrates stayed at 0ppm always. I only did them to put trace elements back in the water every once in awhile.
1. I think Bob Fenner is "the man" when it comes to fish.... ..... and of course his books.

2. I like MH - shows fish colours at their absolute best..... low wattage, mount them high for great effect. But a couple of NO tubes is perfectly acceptable.

3. depends on what you want to keep. I reckon a GOOD skimmer....something way over sized. GOOD flow. No more than 1lb per gallon of GOOD LR.....sand is a matter of choice.... I prefer bare bottom or SSB.... others say DSB.... its a 50-50 decision really.

4. No - do monthly water changes of 25% or more and thats all you need for coraline etc. depends on fish, you mgiht need to change more, but not for calcium sake.

5. Skimmer - A good make like DEltec and go forsoemthing rated for 3 or 4 times bigger than the tank you are getting..... this of course depends on the type of fish and the amount of fish, and how well you feed them. You could get away with less, or might even need more.
I think it is ............. there is a deltec Forum in the sponsors list too..... there are plenty of good makes in the U.S. ...... I just say them because thats what have :) And because they are well know for rating their skimmers properly.... alot of companies "say" 500 gals when they "mean" about 250.......

When tlaking abotu FO (or FOWLR) tanks I tend to think of the "system" as being in 4 parts..... Water / Fish / skimmer / bio-filter.... and its all about "balancing" the system. If you over do certain things you have to compensate with others..... but the only thing you can do without compromise (apart from cost) is the skimming:
Water - well you'll never have too much water, but it gets to a point where as water volume goes up, you need to increase everything else to "handle" it.....
Biofilter - particularly if you are going LR (FOWLR) you can get to a point where too much rock will compromise swimming room.....
Fish - the "variable" that effects all others which we are trying to maximise....

So, by going big with the skimmer, you are building in redundancy. Now there is always a lower limit to the amount of LR you need, but in my view, you only need enough rock to provide shelter for your fish..... a big skimemr lets you do this, without compromising the fish population.....

So, for a given volume of water (the biggest tank you can fit), by having a way over sized skimmer, you can minimise the amount of rock required for filteration purposes, and you find yourself limited only by the terrirtorial requirements of your fish....

Hence, my formula for a FOWLR tank is to go big big big on skimming...... so I would be inclined to look at whatever skimmer a typical sps guy uses on his tank (the same size as yours) and then go for the next size up.