"Predator Tank Playmates" and Algae issues

[eagalldo]

This is my first post, so go easy on me! We have 4 aquariums: 1 freshwater and 3 saltwater (3 reef and 1 FOWLR). We have been having a problem with red algae covering everything, including the sand, in our FOWLR tank. I know that this can be due to high nitrates, but although our nitrates aren't non-existent, they are always in the 5-10 range. All other parameters are always at zero. We have done several water changes, but this algae issue persists.... for months, really. We've also tried shortening the amount of time we have the lights on. All of the inhabitants are thriving, eating well, and look healthy. This will be a 2 part question:

1) Any further recommendations about the red algae? It's pretty bad. It seems to be worse in certain areas of the tank, one side worse than the other.

2) We've been trying to find something to sift or stir up the sand a bit in this tank, which is difficult because it's a "predator tank", of sorts. We've tried small-ish horseshoe crabs, but honestly, I've never even seen the things since they were put into the tank. I'm not sure if they made it or not. We tried that twice. We've tried really large turbo snails, which survive for a while, but then I think they eventually get picked off. I was wondering if a flounder could serve this purpose and survive this tank. What are your thoughts?


The tank in question is a 180-gal FOWLR with approx. 1- 1 1/2 inch fine sand bed and lots of live rock. It's been up and running fine for about 1 1/2 years. If you need to know further details about all of the "technical" equipment, let me know. I'll have to consult my husband on that part. But I do know in rough terms that it does have a sump with refugium (live rock and macro algae in it), a carbon reactor, and a protein skimmer. The inhabitants include:

Miniatus Grouper - ~6 inches
Humu Picasso Trigger - ~4 inches
Lunare Wrasse - ~6 inches
Dogface Puffer - ~5 inches
Snowflake Eel - ~12 inches
Panther Grouper - ~8 inches
(yes, we know he will need a bigger tank soon)


THANK YOU for any and all help!

~Beth

 

[eagalldo]

Oooooh! I love that I automatically have a blue face tang as my default image! LOL I love those fish (but don't have one)!

 

[geridoc]

There are several issues in your post. First, your nitrates are low because the red algae are using nitrates to grow, so there is no point in using up your reagents testing for them. After you get rid of the algae you can go back to testing. Second, Cyanobacteria (the correct term for red algae) need nutrient in the water, generally from over feeding. So, you need to reduce your feeding, but keep an eye on your predators - don't let them get too hungry. Finally, Cyanobacteria thrive where there is low flow, so be sure that you have powerheads creating flow over the sand bed. If all else fails, Cyanobacteria are susceptible to erythromycin, but it is only a temporary fix. You need to solve the nutrient/current issues to really achieve a lasting solution.

 

[cav414]

Im not an expert but I've had a Fowler for almost a year and just recently had a fight myself with cyanobacteria. Geridoc hit the nail on the head with the nitrates. I got rid of it by these steps. 1. Cut back on your feeding, 2. Cut back on your lights (unfortunately I think this step played a part in killing my green star polyp colony), 3. Try to suck as much of the cyano out as possible its slimy and a little difficult to get out but try. It took about 3 months for me to start seeing an improvement and another month for it to completely disappear. As far as a sand sifter, I had a fairly large chocolate chip sea star, I don't know if they are technically sand sifters but he did a great job of eating the excess stuff on my crushed coral. He also stood up very well against my niger trigger, blue damsel ( vicious little guy), Valentini saddle puffer and yellow tail damsel. I also have blue leg hermit crabs and a sally light foot crab that are very active cleaners and are able to stay out of the mouths of my fish.
I hope this helps

 

[honu808]

better flow or different angles on your powerheads and watch over feeding as mentioned will help a lot.