Dear Mr. Goemans,
I hope you don't mind, but I would like to solicit your advice on an issue I'm experiencing with my aquarium. I have a 180 gallon tank with an Eco-wheel for filtration. There is about 200 pounds of live rock, and a 4 - 5 inch sandbed (1/3 crushed coral, 1/3 fine sand, and 1/3 medium grain sand), and no plenum. The tank has been running for about 18 months now and until the last 3 months my only problem was a dinoflagellate outbreak, which I overcame last spring. My tank was improving and I thought by adding some soluble iron that would help the turf algae grow on the Eco-wheel. After the second dose, I started noticing hair algae growing on the rock. I immediately stopped the iron, but the algae had taken a strong hold. I then had a second mishap 2 months ago due to a faulty pump used for replacing evaporation water. This led to the Eco-wheel to stop turning and about 1/3 of the good algae died. This left the Eco-wheel off balance and long story short I ended up scraping a large amount of algae from the wheel to get it to balance again and turn as it normally does. The net result is most of the lower half of my rock structures are coated with hair algae.
I have stabilized the Eco-wheel, and algae growth is starting to come back. I expect it may be fully covered in a red turf algae within another 3 months. There is some green turf but not much. I am able to harvest about 12 once ounce cupfuls of algae every couple of weeks.
My main question is that my livestock have not helped relieve the unwanted hair algae to any noticeable extent. I have scrubbed with a toothbrush and removed quite a bit, but ultimately it returns. The water I use is RO/DI with 2 ppm based on a TDS meter. I use Instant Ocean for salt. I test with Salifert tests and receive the following results: Nitrate: 0 - 1; Phosphate: none detected; DKH: 9; Ca: 420; pH: 8.1 - 8.23 (Pinpoint Meter); and, Salinity: 1.025 (calibrated refractometer).
I have no "mechanical" filter in the tank, so when I manually pull algae there are lots of little pieces that eventually settle. I have added two Dollabella auricularia, which haven't done much. I also have various snails and hermit crabs, which avoid the hair algae. I have a yellow tang that avoids the hair algae (but loves the small pieces from the Eco-wheel). I replace 40 gallons saltwater monthly and use about 3 gallons of RO/DI water thru a DIY Kalkwasser stirrer daily. Lighting is 3 x 250MH x 8 hrs/day and 2 x 80W T5 actinics x 10 hrs/day. And temperature now is 78 - 80 degrees, but in summer/fall the temps can increase to 81.5 before my MH lights turn off.
My plan is to continue manual removal of the hair algae, and alter water changes to 20 gallons every two weeks. My main question is whether you think it would be worth adding a protein skimmer to the filtration or not to export out greater amounts of waste products? I think I can incorporate an airstone-based skimmer that wouldn't completely detract from the reported benefits of the Eco-wheel system. Would you recommend any other options?
I appreciate any advice. Thanks.
Thanks for your email, and always thought the Eco-wheel to be an excellent product. And if it weren't for the 'iron' additions, the unwanted alga, which isn't a true alga as it's a cyanobacterium, would probably not have occurred. And since it's not a true alga or tasty, the animals presently in the aquarium ignore it, including the added sea hares.
And there are two forms, long hair-like (Derbesia) or plume-like growths (Bryopsis), and a slime-like growth. Your water conditions are good enough to prevent the red/slime side of the equation, which is brought about by excessive nitrate and phosphates. Unfortunately the additive brought about a situation that initiated/benefited hair-like or plume-like growth. And once started, these two green growths are usually difficult to overcome, as they can make the majority of their nutrient needs directly under their own base structure, therefore are somewhat independent of the remaining nutrients in the bulk water. And as they grow, they release tiny spores that find crevices to settle in, and then develop further when conditions are right for them.
Where you're concerned, have seen similar happenings with other aquarists where certain mishaps caused the flare up of unwanted species. And where these situations involved water conditions similar to yours, i.e., where nitrate and phosphate were under control and water quality was generally good, I recommended a mechanical method that I previously used that actually proved quite successful, which is as follows: Depending on just how severe the problem is, first remove any rocks which are easily removed and brush them clean in a pail of water the same temperature/salinity as the aquarium. Then, in the more difficult areas use the following method. -- take one of those long wire handle, fairly stiff pipe/tube brushes (something that would fit inside a half-inch ID tube) and securely wind the wire handle portion around a siphon hose which has a three-eights I.D., so that the brush portion is even with the end of the siphon hose. With the siphon action started, scrub the areas of hair algae where it is then either caught on the bristles of the brush where it can easily be drawn into the siphon tube and flow into the waste water collection pail. All water removed is replaced with new saltwater. There's no magic here, as this is hard work, and needs to be repeated as necessary, as I've found it usually takes three good attempts to restore the environment. And it does work, if the water quality remains excellent. I would also add some new 'hungry' snails after each cleaning, such as the Astraea species. Keep in mind they have difficulty getting a foot hold on the long thread-like hair of this type algae, but once you remove the bulk of this type algae, these super great snails will be able to polish off the remaining just as they do the film type algae. This has "always" worked" for me!
As for the protein skimmer, from what I can gather from your letter, your aquarium's environment, including the algae on the Eco-wheel has done very well without a skimmer being used. Therefore, for now, would continue to go that road as you try to fully reestablish the system.
Hope this helps, and keep me posted.