I agree with Capt.
You ain't got hardly enough light to grow a mushroom. So don't worry about putting so much excess light on the tank that it's the cause of your algae. It ain't. If you have a problem with your lights, it might be they are old. As a rule, lights should be replaced at least once a year. Most lights will last a year. Notice I said MOST, not all lights will maintain their designed spectrum for a full year. Some lights wear out after 6 months of heavy use. If your lights are older than 8 months it could be they have lost their spectrum and have started throwing off the wrong spectrum for corals.......... but the perfect spectrum for algae.
Your nitrates are high IMO. You need to get rid of that canister filter right away. Or plan to clean it every 3 days religiously. A canister filter traps detritus (fish poop and uneaten food) where it will rot. It will experience some nitrogen breakdown, but since a canister can only grow aerobic bacteria inside, the nitrogen cycle cannot run fully through to nitrogen gas. The aerobic bacteria simply eat and produce nitrates and thats as far as it goes in a canister. There is no nitrate reduction. There is only nitrate PRODUCTION.
Or......... you can keep it and just run carbon in it for about 1 or 2 days and then take it off the tank. This is how I use my small canister and my small HOB Whisper. Depends on what mood I'm in. Both work. The Whisper 20 is easier to set up, but doesn't FORCE the water through the carbon as well. The small Rapids canister works much better at FORCING the water over and through the carbon graduals, but it's a pain in the ass to fill the media bag, hang it on the tank and secure the hoses, prime it, get all the bubbles out...... but DAMN it works great. I run carbon once a month. I run it on the 30g display for 24-30 hours and then I take it off and slap it right on the 10g frag tank for another day or maybe 2. Then the HOB goes away until next month. I clean it out with hot fresh water, dump the carbon down the garbage disposal, dry it all out and store it under the cabinet.
Your phosphates are high as well. What brand and type of food are you using? Flake food is loaded with phosphates and ash. Ash breaks down into phosphates later on, so it only contributes to it over a long period and makes it all the more frustrating. Feed frozen foods and rinse before you introduce it to the tank. I rinse my food in RO water and only introduce the meaty chunks to my tank. The fish isn't going to suck up that little cloud of food "dust" that you'll see when you drop frozen brine/krill/misis foods into the tank. The fish eat the chunks and the rest of it falls to the bottom to feed your cleaning crew. I'm slowly starving my cleaning crews because I've reduced the food load in my tanks so low that there is no extra. I only put in what the fish will eat in 30 seconds or a minute at the most. Nothing falls down to the bottom. Nothing floats around and gets sucked into my refugium to fuel the cleaning crew, the algae, the nitrates and the phosphates. I've starved 5 or 6 snails and 3 crabs in the last 2 months. Hurray for me!!!
Have you bought a freshwater test kit to test the water coming out of your RO unit? I did. I wanted to make sure my RO unit was working properly so I bought a nitrate test kit, ph, ammonia, copper all for fresh water. That way I can test it once every couple months .......... (like NOW because the mountain snow is melting and we have a lot of spring runoff water coming into our municipal water supplies..... which introduces all the above and other heavy metals)
You need to get a handle on the nitrates and the phosphates. You also need to evaluate the age of your lights.
I have a 30g display and a 10g frag tank. BOTH tanks use a HOB refugium with a built in skimmer. BOTH refugia have a nice DSB to deal with nitrates. BOTH refugia have a big ball of cheato macroalgae that I trim back occasionally and discard in the trash. It's natural nitrate reduction. Fuel the good macro algae in the refugium where I can control it. That starves the algae in the tank where I don't WANT it. Cut the macro algae out and toss it. Nutrient export. :Cheers:
I had a BAD algae problem a few months ago. My T5 HO lights were over a year old and I knew I needed to replace them, but lack of funds...... you know. Finally the lights started to burn out and I had to suck it up and buy new ones. $150 later and 2 months........ my algae is GONE. By doing something as simple as replacing my lights, it threw my tank back into the right color spectrum to promote CORAL growth and not algae.
If you can figure out a way to keep your pH consistently over 8.3 and under 8.5 you can just about guarantee no algae problems. Algae loves our reef tanks because most of us struggle to keep levels around 8.0 or 8.2...... if you figure out a way to keep a reef tank at 8.4 without dosing all kinds of buffers and running a dosing pump full of kalk... you'd be a rich man my friend.
