need help changing to fish only tank

After 10 years of maintaining a reef system with corals, I have decided to change to a fish only tank.
I have experienced too many upsets recently with algae problems that I want to make a change.
My set up at present: tank 46" x 24" x 18", filtration through live rock only, no refugium,
4 power heads, skimmer, T5 lighting.
My question: what procedure do I need to follow to ensure I have a successful conversion to a fish only tank?
I know I will have to purchase an external filter system - what capacity? brand?
I assume I will have to throw out all the contaminated live rock and start again.
What should I replace it with for pleasant and not too costly decoration, similating a reef aquarium?
Will I need a sand bed?
When I have emptied the tank and cleaned it up using vinegar, I thought I would use my wife's steam cleaner - good idea or not?
I intend to clean the powerheads in vinegar as I fear water flow was a cause of algea originally.
While the tank is being cleaned, I will keep my 10 fish (some 10 years old) in a small tank I have borrowed, using one power haed and regular partial water changes. Is that okay or any other ideas.
If you can come up with a sequence for the process I need to follow (an idiots guide will be great) I will be very pleased.

Hmm, a fish only system is really the same as a reef system just without coral.

Perhaps a better place to start is to help figure out your algae issue. We'll need the following info:

What does the algae look like? (pics would be best!)
How long have you had it?
What have you done to try to get rid of it?
How many lbs of live rock do you have?
How much flow do you have in your tank (you sig says 4 powerheads - what brand, how much flow does each give, where are they placed, when was the last time you cleaned them)?
What do you have for a clean up crew?
What are your nitrates and phosphates?
What, how much, and how often do you feed?
What type of fish do you have?
Do you have any sort of filtration other than live rock (sump? skimmer?)
What type of lights do you have? If t5 or MH, how old are the bulbs?
Have you tried macro algae (chaeto) in your tank?

That's all I can think of for now, but others might think of more questions! Most algae problems can actually be solved pretty easily unless it is a more challenging strain of algae, but even those challenging strains can be resolved. Let's see what we can do to help you get your tank back to where you want it!

+1...all you need to do to make the switch is to remove the corals. Finding the cause of the algae will probably be easier than pulling everything out and starting over. Start doing weekly water changes using saltwater made with ro/di water if you aren't already doing so, change your bulbs if they're over a year old, and add a bag of phosphate removal media to your tank. Good luck.

• To FishyReef and others - thanks
• Here is the info you require
• Take a look at the pics attached. As you will see, the red/brown slime algae is every where in the tank. I have purposefully left the tank untouched for two weeks to show the extent of the problem
• The algae has been there for 3 months
• I have changed the four T5 lights three months ago,
• 15% Water changes every week
• regularly test water quality
• PH 7.9 (is there a clue in this reading?)
• Ammonia 0.0
• Nitrite 0.0
• Nitrate 0.0
• Phos 0.0 / 0.25
• approx 25lbs live rock
• flow (this is a problem - 4 low efficient smallish powerheads that tend to get clogged up quickly)
• clean up crew 8 turbo snails, red / blue leg hermits tend to die after a few months
• brittle star (7 years old)
• feed - one small cube of frozen (mixture) brines shrimp etc.per day
• fish: 6 yellow tailed blue damsels, 2 clown, 1 queen angel, 1 yellow tang, 1 wreck fish
• only filtration is live rock
• no sump
• no macro algae
• RO system replaced two months ago
• effective skimmer

So, there it is. I am about to do a water change now (after taking the pics) and I realise that I need to up the flow of the water. I have cleaned the power heads in vinegar solution but suspect you will tell me that I need to replace them with more effective and stronger flow power heads?

I am at tethers end now and am desperate to resolve this problem without spending bucket loads of money.
I await your response and thanks all again.

I sent old pics (not too clear) in last post,so please look at these that will show the problem more clearly

Wow, that's bad! Looks like cyano and hair algae. Excess nutrients and phosphates are likely the source, and I suspect limited flow is a big contributor as well.

Am I right that your aquarium is around 100 gallons or 380 liters, and that you only have 25 lbs of live rock? If so, you definitely need to up your amount of live rock - we try to aim for 1-2lbs per gallon, so you'd want 100-200lbs in your tank to help process the nutrients.

The RO unit you have - is it an RO/DI unit, or just an RO unit? You mentioned you replaced it a few months ago - if you can give us a link to the actual unit that might help answer some questions!

You mention 4 powerheads, but now how many gallons per hour each is rated for. In a reef tank we try to aim for 30-40gph turnover in our tank. So for a 100g tank you want 3000-4000 gallons per hour flow in your tank. If your powerheads are providing that much flow (I highly doubt they are given the algae growth), then I'd try repositioning them to point directly at your rocks.

I'd strongly look into setting up a sump for your large system. You can make a sump out of a rubbermaid tub and HOB overflow box. I know most people prefer drilled systems, but I have an HOB overflow and haven't had any trouble with it. With a sump you can put a ball of chaeto macro algae in it, put a 6500k bulb over it from any local hardware store and get some decent flow going through it and the chaeto should help by out competing the problem algae for nutrients.

You might also want to consider upping and diversifying your clean up crew - 8 turbos and a brittlestar is really small for a 100g tank. I'm linking to a site called ReefCleaners that offers cuc packages based on tank size - I know you're in the UK and not able to order from them, but it should at least give you an idea of how many and what types of snails, etc., you should be looking to get for your tank. I personally prefer just a snail based cuc because the hermits kill the snails over time, and the snails are going to be good algae eaters (at least for the green-based algae you have). www.reefcleaners.org

What brand protein skimmer do you have? Again, providing a link to the model might help! Some protein skimmers look like they are doing a good job when they really aren't pulling out much and people often don't realize that until they get a good skimmer!

The cyano (red slime) that you have is probably feeding off of phosphates in your system. Phosphates tests are notoriously inaccurate and really hard to read because phosphates only stay in the water column for something like 7 seconds before being consumed by algae. If your test says 0.25, then you definitely have a much larger phosphate problem then the tests indicate. Food can be a big contributor to phosphates. I think brine shrimp can be high in phosphates and I'd recommend switching to a different type of food and cutting back to every other day. Do they sell brands like marine cuisine or emerald entree in the UK? Also, brine tend to be like candy for fish - yummy but not very nutritious, so switching to mysis or a mixed food like the other two I mentioned will be better for your fish as well as your phosphates!

Lights - I find it interesting that the problem has been around for 3 months, around the same time that you switched your bulbs. What brand of bulbs did you go with? I wonder if the bulbs were bad and have shifted into the more red spectrum (which you might not see with your eyes, but which would promote algae growth).

Finally, while you work on figuring out the source of the problem, there are a few things that can help manage it in the short term. Next time to you do a water change, take a turkey baster or one of your powerheads and blow as much of the red algae as you can off your rocks, and then suck it out with the siphon when you change your water. I'd probably do a slightly larger water change so you can suck out as much as possible. You can also suck out the algae on the sand bed with the siphon hose. If your rocks aren't glued in, then you might want to pull then one at a time and scrub them off in a bucket of tank water to try to manually remove as much of the algae as possible. I know its going to grow back until you figure out the source of the problem, and it might take months to really combat it and get it to go away, but at least in the short term it will help remove that stuff from your water!

+1 Fishy,

I have to say, Fishy, that was an excellent post. I haven't searched a whole lot on the site, but it seems you could pretty easily expand that into a small how-to guide of some sort. Think you might be willing to give that a go?