Hi everybody! First of all I would like to congratulate this great source of knowledge about algae scrubbers and thank Floyd for beeing so suportive on this subject. The main purpose of my discussion is long story short: how to keep LPS coral healthy when using algae scrubbers. I've recently built an ATS to improove my tank filtration and keep bubble algae and GHA, which I assume is a bryopsis or derbesia type, at bay. Before ATS I've been keeping successfully my tank for more than 6 months with only a chaeto refugium, however, bubble algae and this GHA kept growing as well as my corals. Nitrates have never been more than 5 ppm and phosfates always below 0.08 ppm - according to Red Sea Pro test kits. After making my DIY ATS (5 square inch screen with 5 - 3W LEDs on both sides), my LPS corals are not so happy as they used to be. My war coral and a goniopora has some tissue recession, even though I'm target feedin reef roids every day. My tank has 5 fishes (2 clown fishes, 1 six-line wrasse, 1 clow goby, and 1 yellow tail damnsel) and I a lot feed them 3 times per day. The nitrate tests now always read 0ppm and phosphates are at 0.04ppm. Did anybody has had this kind of issue? Thanks.
Some additional information I forgot to mention: - The flow on my ATS something about 1000L/h (265 gph). I have a 2.000L/h return pump and the ATS is fed by the overflow line. - ATS is lighted on 15h/day. - Soft corals and SPS corals are doing fine. Specially some zoas, GSP and a Leather coral - I don't know if its something related to daily dosing of phyto and the reef roids. - I use GAC and change it every other week - I'm still using the chaeto refugium. The chaeto is growing slowly, but is still growing. - The bubble algae has stoped growing crazy as it used to be. The derbesia or bryopsis GHA has slowed growth. - Some cyano is starting to grow on the display tank sand
You beat me to the suggestion to use GAC. How much do you use? The cyano is usually the last to go, after your nutrients are down and GHA has less available fuel in the water column, that's when cyano usually pops up. It could also be part of the maturing process of your system. See #15: Mything the Point, Part Three: Conclusion - Reefkeeping.com Your flow of 265 GPH over 5" of width means you're running around 50 GPH/in of width - is that actual (measured) flow, is that your pump rating (max flow) or is that pump minus head loss (calculated flow)? If it's actual/calculated, that's a bit on the high end. That's not necessarily a good thing (I used to think that higher flow was always better). Coral warfare is always a possibility. GAC can't always take care of that. This is one reason why water changes still are in play, the "chemical soup" that some corals create when fighting each other can get thinned out or muted with water changes, and this allows the "losing" corals to have a better chance of building up a defense, if they are able to. If that makes sense. Regarding the bryopsis, are you sure that's what it is? If so, you might consider fluconazole tablets. Bryopsis Cure: My Battle With Bryopsis Using Fluconazole but make sure that's what it is...
I normaly use about 100g of GAC and change it every other week. I thoght too it could be a coral warfare, so tried to change the GAC more often and feed more the corals (reef roids) and the fishes, but LPS corals continued to be unhappy and goniopora receding tissue. However I made an experiment last saturday: dose potassium nitrate to adjust nitrate level to 2 ppm. The same day and on Sunday I noticed LPS seemed more happy and extended polyps more during the day (specially my acan, lobo and goniopora) and the feeding tentacles during the night. One dawback is the bubble algae I am constantly manual removing from the tank visibly grew faster on this two days. My tank is 2 years old (30 gallon DT + 20 gallon sump) and I've had a cyano outbreak which disapeared when my tank was close to 8 months old. So I think the mature variable might not be the issue. I think the algae I have here is some kind of derbesia or bryopsis, but I'm not 100% sure. The algae grows on very low nutrients and attach to live rock so hard that I can't easily manual remove it. It seems to have roots inside the rock, just like derbesias and bryopsis do. Thats why I assume it is a kind of derbesia/bryopsis. I tried the fluconazole dosingt when my tank was 6 months old. Since 2014 people from Brazil has been using it with mixed results. I didn't make a dent on the algae strain I have. Some turf algae that I had on a trumpet coral has died but the stuborn algae on the rocks did not. Maybe I have one fluconazole resistant alga strain. One thing you said about the flow may be an issue why I am not having heavy growth on my screen. The 265gph was calculated and maybe the flow is on the high end just like you said. One thing that I noticed is only short GHA grows on my screen and on the botton of the ATS I have a lots of long GHA which I have to constantly remove. Do you think this lack of long GHA on the screen might be a flow issue?
Hard saying, but it's possible. What light are you using? Can you post a pic of your scrubber setup? You can dose K pretty heavily, and go to as high as 1000 ppm (according to Justin Credable, he spoke at one of our fests about Gonios actually) Justin doses iron (use the RHF recipe or crushed tablets of the correct kind) and potassium, the latter gets $$ if you are running a scrubber (which sucks down the K) so I suggest getting yourself a 40lb bag of potassium water softener salt at Home Depot for $25, much more cost effective. What you do is mix it up in a bucket (saturated solution) and then take that and drip it through dry GFO to get rid of impurities, then dose that. Or drip through GFO right into tank. Cheap solution and I believe you can safely dose an increase of 20ppm/day (which is a lot of solution).
I'm using 4 Deep Red 660nm + 1 Violet Cree XPE LEDs on both sides. I dimmer each array to 400mA. As you can see by the above photos, the growth on the screnn is short. However, the growth at the botom of the ATS chamber is pretty long. I was just aiming to dose nitrates. Great advice about potassium dosing. Thanks.
I couldn't link the photos to Google Photos directly. So lets try the plain links: https://goo.gl/photos/xpaBcMGFQ1bnfgph8 https://goo.gl/photos/9nRoicLouTxMPN859 https://goo.gl/photos/TPxweDWK2Wt6CvDk7
I would check your flow rate by measuring it first, but ideally you would want about 170-180 GPH as a baseline. Unless you have a reason to go higher, don't. i.e. high nutrients, etc. There is a balancing act between { flow & nutrients } and { photoperiod & intensity }. Mainly intensity, because that is instantaneous (meaning, the light has to be able to be adsorbed by the algae or else funny things can happen). Once you have that balance down, i.e. mature screen, consistent growth, then extending the photoperiod draws out the total adsorption rate throughout the day, and this is a slower overall process than cranking up the intensity (which can cause photosaturation quickly). Drawing out the photoperiod means that over time, you might end up reducing nutrients down to a point where the incident light (intensity) is a bit too much, but this is a more stable way of "tuning" your scrubber do your tank.
So for Google Photos, what you have to do is open the photo link, then click on the photo to get it full screen, then right-click on it and select "Copy Image Location". Then come here and click the photo icon on the reply box toolbar and paste in that link.
