So I fought this very long battle that you are fighting right now and I’ll give you tips to overcome it. I left my home in NYC for Florida for 3 months during the outbreak of Covid and left the tank with an autofeeder. Long story short the tank was overrun with nutrients and I had massive long strands of this stuff that took over all the rocks. I’ll give you the recipe that eventually worked but it’s going to take some work. This is about re-establishing bacterial harmony to your tank and less about pure chemistry.
1. Manually remove all the algae by hand. I did this by tearing off the stands where I could and manually removing the rocks and brushing them with a toothbrush. I wouldn’t suggest using hydrogen peroxide, I tried it and it didn’t work for me and I have a theory as to why...I’ll cover it later.
2. Remove as much detritus as you can from the tank. This is where all the algae gets it’s power from. I had compartments in the back of my Biocube that had never been cleaned and it was covered in detritus. If you have a sump, clean that out, a bucket head wetvac from HomeDepot for $25 is a godsend. Also, gravel clean your sand until it’s as clean as you can get it, there’s tons of detritus in that.
3. Once all the algae is removed, sand is cleaned, and detritus is removed then you’re ready to go to work on building a healthy bacterial environment. You can start adding some bacteria to the tank like Dr. Tims Waste Away to seed your tank with more beneficial bacteria, or just carbon dose which will multiply your existing bacterial populations. This is why I don’t like nuking rocks with hydrogen peroxide because it wipes away all the beneficial bacteria as well as the algae making it easier for the algae to just outcompete the beneficial bacteria. Make sure to watch your levels during this time and don’t let your nitrates and especially your phosphates hit 0. This could cause stress to the corals and other issues like dinoflagellates.
4. Make sure you create the right flow patterns in your tank. If there are lots of dead flow spots, make sure to add flow. This is very important to keep detritus from building up again and causing the same issue. Make sure your detritus stays suspended in the water column and flows into your filter socks.
5. Your algae will likely come back again, but this time not as aggressively. This is usually due to your rocks still containing some detritus/phosphates. Manually remove as much as you can each week. Even if you’re just going into the tank with a toothbrush and brushing it off the rocks. Make sure to clean the filter socks after each cleaning. Again we want beneficial bacteria overtaking the place where the algae used to grow. This phase is where it’s great to have a solid clean up crew. Most snails will go after hair algae when it’s short, in my experience once it gets too long they won’t eat it. I like torchus snails and urchins as they are hearty and won’t die off easily. Make sure your clean up crew isn’t dying off and adding to your issue here.
6. Make sure to feed only frozen food from now on. Don’t feed processed dry foods as this will likely add too many phosphates that your tank does not need.
7. Watch your levels and try to maintain a 200-300 part Nitrate to 1 part Phosphate ratio. So for example if Nitrates are 15 then your phosphate should be anywhere between 0.05 to 0.08. I believe ratios are more important than a hard and fast level you have to achieve. Adding only frozen fish food will almost automatically ensure you keep this ratio as they are nitrate and phosphate balanced to begin with.
The reason I and so many others failed at previous attempts to rid ourselves of hair algae is because we saw it as a water chemistry issue and not a bacterial issue. When the only tool you have is a hammer (chemistry test kits) everything looks like a nail.
Please keep us informed of how your battle goes. You can win this battle, it just takes time and the right game plan.
