Who Gives A Fish Forums

Yeah I'm pretty sure that's a penguin filter, not top fin. I've had my fair share of experience with them, having owned three so far. Only one of them gave out on me, but that's beside the point. The wheel on that thing can actually add some extra oomph to your biological filter, which is definitely a plus.

dreamon7 wrote: ↑Mon Jun 23, 2025 7:36 am I'd get the RO/DI unit first, it's one of those things you'll keep putting off if you don't just do it now. Then I'd focus on adding more live rock, it's always better to have more. After that, consider getting another powerhead - I think you'll find it makes a difference. Have you looked into Tunze Turbelle?

Thanks for all the comments guys, I really appreciate it. I have to admit, I've made some pretty bad decisions so far. I visited one of my LFS, Congressional Aquarium, and asked for advice on starting a saltwater tank. They told me it's basically the same as freshwater, just double the filter size. They also said I should start with at least a 30g tank. Well, I took their advice and bought a 30g tank and a Marineland Filter for a 75g tank. I know, I know, it was a mistake.

I then started asking questions on this forum and everyone said I needed at least a 55g tank, and it should be 4ft wide. So, I returned the tank and upgraded to a 55g. After that, I started talking to Mr. Coflake at my new LFS, and he told me that live rock is the way to go for filtration. He said the Marineland filter I bought would work, but it's not a long-term solution.

That brings me to where I am today. I've got a 55g tank, and I'm running a Marineland Penguin 350 filter. But my goal is to get up to 55lbs of live rock and use that as my primary filtration method. I'm actually about to buy more live rock in a couple of days, and I'm planning to add it to the tank as quickly as possible.

I do have a couple of questions though. Rusticore, you mentioned taking the fish out and letting the live rock cycle. But how does that work without ammonia? I'm genuinely confused. And as I keep adding live rock and doing frequent water changes, can my fish survive? I'm a bit worried about that.

Thanks again for all the advice, guys. I really appreciate it.

Live rock already contains living bacteria and dying organisms that release ammonia. Even semi-cured rock, which most stores sell, has enough dying organisms to fully cycle your tank without harming fish. Fully cured rock has no dying organisms but lots of bacteria, instantly cycling your tank.

Since you already have fish, you can cure the rock outside the tank in a separate container. Look for cured rock and cure it again as a precaution. When the rock is done curing, add it to your tank. To find the most cured rock, sniff the container - if it smells rotten, it's uncured, but if it smells ocean-like without the rotten egg smell, it's probably cured.

Cured rock has no dying life, so it won't spike ammonia. Uncured rock is the opposite. Test daily or every other day, and if there's ammonia or nitrite, do a small water change (10-15%). There probably won't be much with just one small fish in a big tank, but don't add more fish yet until your filter is filled with bacteria or you get some cured live rock in there.

By the way, there's no "good" tank size to start or minimum size. The bigger the tank, the easier it is to maintain water quality, but it may cost more. I started with a 20-gallon nano, and it's great.

While I agree that there isn't a one-size-fits-all starting size for marine tanks, if I had to pick one, I'd say 30 gallons is a good benchmark. My personal experience with a 14-gallon tank was a bit of a struggle, and I soon found myself upgrading to a 30-gallon tank, which proved to be ideal for learning the ropes.

The advice to double up on filtration is somewhat ambiguous. In reality, you can get by with minimal mechanical filtration, especially if you're running a FOWLR tank. A well-stocked tank with live sand, sufficient live rock (about 1.5 to 2 pounds per gallon), and ample flow can provide more than adequate filtration. It's only when you're dealing with more sensitive livestock that you need to bring in the big guns.

Regarding adding live rock to your tank while keeping fish or inverts, it's perfectly fine as long as the rock is properly cured. If you're sourcing your live rock from a nearby LFS and it's not being removed from water for extended periods, you should be good to go. However, if the rock is taken out of water and flow for a while, you may encounter die-off, which could trigger a mini cycle or worse.

One thing worth mentioning is that, while many people swear by not needing a skimmer or filter when running a FOWLR setup, I'd argue that if you don't have a sump, a skimmer can be incredibly beneficial. It'll help remove impurities that your filtration can't pick up and also help reduce algae and cynobacteria. Of course, it won't cure either of these issues, but it'll definitely help.

Regular water changes and monitoring water quality are still key to maintaining great water quality. Then, you can take action as needed.

As for flow, the higher the better, usually. There's no upper limit, really.

Regarding CUC, I think they're hardier than livestock, so if your water parameters are acceptable, start adding them slowly. Let's be honest, if your clown is doing fine, the CUC will be fine. Plus, your CUC won't add much to your bio loading.

When it comes to cured LR, if you regularly use a reputable LFS, they should be able to tell you how long the rock has been curing in their tanks. I personally don't touch anything that hasn't been there for at least 4-5 weeks, unless it was cured before they got it – which isn't normal due to cost. And, as rusticore mentioned earlier, the smell is the biggest giveaway.