[Travis L. Stevens]

Here are some ideas where the extra nutrients could be coming from.

--Canister Filter: These are aerobic filters that leave little to no room for denitrification to occur.
--Refugium Lighting: An increase in lighting or bulb replacement might help add quicker growth to your macroalgae. Make sure that you harvest as much of it as possible as often as possible to take out all the concentrated biomass.
--Tank Lighting: Your bulbs could be rather old and have shifted to a more favorable lighting color. Also, if sunlight is shining on it, this could also give more proper lighting for algae.
--Water Change: Increase the amount of water changes. 5% isn't much even if it done weekly. I would go with 10%-15% weekly.
--Water Change Water: What is your water testing at before you put it in?
--RO Water: Are you sure that the water you are getting from the LFS is properly filtered? When was the last time they replaced their filters? Does it test zero across the board? What is the TDS?
--Fish: Five fish can be a lot. What are your other fish? There could be a large bioload as well as a large amount of Carbon Dioxide buildup that is fueling the growth of the algae.
--Cleanup Crew: Your cleanup crew is quite large and inadequate. Though they help keep things undercontrol, they also produce waste. And their waste is a lot easier break down to Nitrates quickly. Also, Nassarius snails are more of a scavenger than an algae eater. So, there is a lot of unneccessary waste being produced from them alone. Also, conchs aren't very good as a clean up crew and quickly deplete sand bed fauna and flora. Their waste production is huge.
--Scrubbing: Though you scrubbed the rocks, you may have made the problem worse. You have now spread the algae and it could come back stronger than before.
--Rock Work: Make sure that there isn't a buildup of debris or uneaten food on the rock work. This is where algae will first start to grow.
--Water Flow: Your waterflow could be inadequate. If there isn't enough flow to keep detritus in the water column to be taken to the skimmer, then it would eventually be a source of nutrients
--Missing Livestock: When live stock goes missing, most likely it is dead. And that in turn will break down into more nutrients. Make sure that you remove all carcasses.
--Feeding: Make sure that you are not feeding heavy and that all the food or almost all the food is eaten. You might even want to switch to feeding once every 3 days.
--Knowledge: Make sure that you know what algae does. Though unsitely, it is getting rid of excess nutrients. As long as the algae isn't harming anything, then leave it be. It will eventually use up the available nutrients as long as you aren't creating more of it. Then, as it starts to die out, you can pull it out before it has a chance to decompose and return to the water as nutrients again.
--Testing: Remember, you might be testing zero, but you have to remember that the algae is most likely taking it up before you have a chance to test it.

And above all else, post your water parameters

Temperature:
Specific Gravity:
pH:
Alkalinity:
Calcium:
Ammonia:
Nitrite:
Nitrate:
Magnesium:
Phosphate: