Am I combating GHA correctly?

[t5Nitro]

I am now starting to do 5 gallon water changes on a regular basis, and I'm siphoning out green hair algae as I do it. I just take a brush and scrub the rocks while I hold the siphon tube over it. Really, not a lot of it is able to be removed per 5 gallon water change, but you can really notice a difference. A lot of "dust" floats around the water while scrubbing. Is that sort of a sign of detritus build-up or something and a possible cause of the green hair algae? Are the rocks holding NO3 and PO4 within them? If so, what is the best route to get around that? I've been fighting this stuff since March. Every time I do the water change though for sure I put a filter sponge in front of the main drain and remove and dispose that the next day. Am I taking the green hair battle algae the best way or is there a better way to do it?

Thanks.

[Mariner]

IMO, water changes and scrubbing are a good way to fight green hair algae, but you may need to do more.

First of all, a 5 gallon water change isn't going to accomplish much in a 125 tank, unless you're doing that much every day.
Something on the order of 20+ gallons per week for awhile would be appropriate, vacuuming out all the detritus each time. (I'm assuming you're using good RO/DI water for your new saltwater).

Second, you should check nitrates and phosphates with a good test kit. Reduce these by stronger skimming, growing macroalgae in a fuge and running GFO.

Third, feed less.

Fourth, get some good herbivores. Turbo snails are said to eat some GHA, and some tangs will go for it.
HTH,
Mariner

[shuguley]

I was getting over-run with green hair algae in my fairly new 55 gallon. I was doing like you, scrubbing and siphoning. Well, I added chaeto to my fuge and a phosban reactor to my sump, once the chaeto had abut a week to start growing and the Phosban reactor had a couple days to run, the green hair algae literally quit growing overnight.

Now my tank looks like it never had green hair algae, and I haven't scrubbed for over two weeks. IME, chaeto and a phosban reactor have worked wonders!

[Sk8r]

shuguley is right. One or the other. If you have algae, you have phosphate, no matter what the tests say: they can't read what's in the algae. And yes, phosphate comes in the rock and sand. And fishfood. And conditioned tapwater.