If I start a FO saltwater tank, could I convert it to a FOWLR in a year or 2.?

Question

I am kind of tight on my budget now, but could easily afford a FO tank, but not the $750 for live rock for a FOWLR set up. So my question is could I convert a FO tank to a FOWLR tank while keeping fish in the tank, and not restarting the nitrogen, ammonia, etc. cycles. Thank You!

Answer 1

Yes if you start with some live sand (make sure it cycles) and foundation rocks in place. You can add the live rock later. The only thing to make sure is that the rock is curred first. In other words put it in a bucket with a air hose and power head. fill it with salt water and let it go through its cycle. When its done you can add it to your tank. If you buy curred live rock then you can add it right away. The best water to use is the water from your existing FO tank.

Good luck.

Answer 2

Yes, but the live rock would need to be cured very very very well. But you don't have to g out and spend that much on rock. I spent $20 for live rock in my 20 gallon aquarium. I would highly reccomend buying some for cycling. I would not pay over $5 a pound, if you are your getting ripped off. Make sure you cure it or buy it cured. But get some rock, FO tanks have higher mantience since you loose the biological filtration. Any questions E-Mail me!

Answer 3

I have never seen a FO tank before.You need some type of media for the bacteria to live in or your waste will build up amonia and you fish will die.I would recomend geting some liverock to kickstart your cycle,maybe just a few chunks to start off with.

Answer 4

How large is your tank? You will need to have something to cycle your tank, whether you use live rock, live sand, or fish. Rather than jumping into this, take a moment to make sure you understand some things about your options.

Option 1. Using live fish to cycle your tank. This means dry substrate, preferably aragonite "sand". Regular sand or aquarium gravel may be cheaper, but they don't buffer your tank against changes in pH. The aragonite reacts with the water to keep the pH from going below 7.8 - even this isn't ideal, as the pH should be above 8.0 for fish, but the difference between 7.8 and lower may mean the difference between your fish doing okay or dying. Since most marine fish are territorial and like to hide out at times, they should have some "cave" structures which can be made from dry carbonate rock (reef rock, reef bones, lace rock, travertine, there are several varieties for about $1.50/lb), or PVC pipe cut into short lengths (not the most attractive, but it gives the fish the security they need not to fell stressed. You can use a few hardy fish (I don't recommend damsels because these are aggressive and territorial - any fish you try to add after them will be terrorized/killed.) to cycle the tank. PROS: This will be one of the cheapest methods, especially if you intend to keep the fish you use to cycle the tank. CONS: If the fish aren't species you want to keep, you may need to find another home for them (stores won't always take them on return), or they may die from ammonia/nitrite exposure. This method may need 3-6 weeks or more for the tank to be safe.

Option 2 - Fishless cycling - Similar to the first, but without adding fish. Instead you use an old filter pad or some substrate taken from an established tank (if you know someone who has one without algae or disease/parasite problems) to "seed" your tank with the bacteria. You still need to add the cave structures and food as an ammonia source, and it will shorten the cycling time. PROS: As cheap as the first, possibly cheaper if you aren't buying fish you can't return; shortened cycling time, no danger to fish. CONS: You will still need to wait longer to have the tank fully cycled unless you can add LOTS of borrowed substrate/filter media.

Option 3 - Using live sand to cycle. You can add this prior to your fish, and add a bit of fish food to decompose as a source of ammonia. You'll still need to add cave structures as above once you're ready to add fish. PROS: The tank cycling time is shortened, but it may still take a few weeks to cycle. It's also safer for the first fish added. CONS: This method will about double your substrate costs. I've also seen bags of "live sand" that have sat on store shelves to the point of gathering dust - makes you wonder how much is still "live" when you get it. Plus, I've also seen cyanobacteria (something you DON'T want) growing in some bags.

Option 4: Using live rock. Here you use live rock instead of live sand. Pros and cons similar to that in option #3, but you could substitute the live rock as the dry rock used to make the cave structures. At $7.99/lb and up if bought locally (buying online may have a cheaper intial cost, but figure out the entire cost with shipping and it may be equal or more!), but will aslo increase your costs.

All the "live" in live rock or live sand refers to is that these have the needed bacteria to detoxify your fishes' wastes. In time, you'll have this no matter which method you use as the bacteria colonize surfaces which don't already have them. What I've done in my own tanks (and would suggest to you) is this. Skip the live sand altogether and buy a FEW pieces of live rock. For the rest, follow option #2. If you get dry aragonite sand and mostly the dry carbonate rock for "caves", you can build most of the structure you need, then place the better quality pieces in front and at the top where they'll be seen. You'll save on your startup expense but still have the live rock to colonize the other rock and sand with bacteria (plus the other "goodies" that come with live rock like shrimp, snails, coraline algea, etc). In a few months, all your rock will pick up enough life that it'll look like you bought all live rock.

Although your method will work in the long run, the disadvantage is that even if you buy "fully cured" live rock to add at a later time, you'll always get some dieoff as the rock is moved. So this would either expose the fish in the tank to some ammonia and nitrite (although you'll have some bacteria built up to help deal with it, so it won't be present as long as if you were just starting your tank, but why risk all your fish you have by this point) or using a second tank/tub to cure the rock separately (which will add the expenses of the second container, heater, powerhead, and salt).