Thoughts on over skimming
 

Anyone have experience on over skimmed tanks? I'm starting to think my tank is being over skimmed as I'm noticing a decline in some LPS coral health. SPS corals are doing well with good color but LPS corals like acans, brains and lobos are beginning to suffer. I've always noticed that LPS corals do better in tanks with more organics and SPS corals are the opposite. In order to find a healthy balance I'm considering running my skimmer on a timer to only skim overnight.

Any thought or experience would be helpful. I run a BK SM 250 on a 120 gallon system.

Do you have any remaining nuisance algae?

I have noticed on tanks that I considered to be over-skimmed that coralline, pods, and micro-inverts (like spirodid worms, mini feather dusters, etc) all but died off. I have also noticed that it's difficult to keep SPS and LPS in the same tank and have them all equally healthy and bright without fairly heavy feeding. Do you feed the corals any meaty foods or additives like Zeo or Fauna Marin? I have really noticed an improvement in LPS since I started using Coral Vitalizer and Sponge Power.

I'm going to go over to the Zeo forums and ask a similar question as I've been meaning to for awhile. As I have gotten quite quickly into SPS lately (since my lights were burning the LPS) I have been getting more and more into Zeo and I worry about the future of the currently healthy LPS due to the forthcoming ultra low nutrient system. I will report back if you'd like.

I severly overskim my tanks and got fantastic results, remember if you are over skimming you have to pay closer attention to your water peramiters, and make sure your compensate your feeding, ie feed more often or feed more as good skimming will remove waist food faster.

I had LPS and SPS, worms, Pods. which thrived in my overskimmed tanks, and had to scrape coraline algae off the glass every day, so I don't think overskiming is your problem as much as water peramiters/light/ect.

My Brain grew from a 3" base to a 6" base in about 6 months, mushroom became such a problem I had to remove them as they were taking over, and SPS gave me amazing growth rates.. all while using a skimmer that was probably rated for 6X the system volume of water. I ran the skimmer so it made a fairly dry foam, ran a Co2 reactor, Kalk reactor, sever water flow (aprox 120X turnover) but I did run a slightly elivated Alk, I liked 1.026 for salinity, 11 to 12Dkh, about 380 to 400 Ca, 1400 Mg, and my Ph was always around 7.9 I ran two AB 10K SE bulbs driven by M80 ballasts on a 3 foot tank plus two 3 foot VHO actinic bulbs overdriven about 14%. the tank was bare bottom, but I built Pod piles behind the rock work. I find the bigest mistake people make is not building pod piles as this gives them a place to grow with out worry of preditation. I had two mandrins and they always were eating pods which I feel was due to the pod piles as they mandrens can't get into them, so the pods can reproduce like mad and as the populatin increases they spread through out the tank.

Steve

I do have a few kinds macro algae kicking around still, but nothing serious. I don't really have much that eats it though but it is slowly decreasing. For the most part this algae is limited to the back pane and a small section of rock at the front of the tank. The rest of the rock is bare with no forms of algae. Coraline is very limited, I maintain a lower Ca (400) and Alk (8) than most and I've avoided introducing coraline as I'm not a huge fan, it's hard to clean and can become overwhelming. Pod population is good but the other stuff is limited, the tank is still fairly new and the rock was cleaned and re-cured from my previous setup so the transfer was also limited.

I do feed some meaty foods from time to time and I probably should be more aggressive but I've found lately that feeding tentacles are not showing up as often. Also some LPS corals are still doing well, such as dendo, chalice, trumpet, duncan, and closed brains. I try to avoid those power foods and I think they tend to do more harm than good but would be willing to use them again if results would improve. I definitely would consider dosing some zeo products again like LPS amino but currently I'm not dosing anything of the sort and would prefer to find the root of the problem first and then add certain things for further improvement.

If you do post on Zeo and get some relative information please let me know and send me a link. That would be much appreciated.

What water parameters are you referring to? Anything I can test seems fine and I do 10% weekly water changes with RB salt. I don't have heavy light in my tank and I keep my LPS lower or in shady areas. The LPS did fine at first but lately a decrease in health in some is obvious.

From my experience higher nutrients results in healthier LPS, my first reef tank was an LPS tank, basically skimmerless and I never fed them, never have I had LPS corals as healthy as they were in that tank.
http://i11.photobucket.com/albums/a1...ishtank064.jpg


I'm willing to sacrifice some SPS color for healthier LPS, i would actually prefer to keep a more LPS dominant tank. Can any one see any potential problems resulting from running a skimmer on a half duty cycle over night?

Low nutrient levels will cause a decline in LPS health, but it is not necessarily caused by your protein skimmer. It is more likely an issue tied to nutrient export such as water changes, algae harvesting, and other chemical filtration methods like carbon and ion exchange resins.

LPS & SPS don't readily mix in nature, so our expectations are generally over-optimistic when it comes to a mixed captive reef. Target feeding may be the only compromise of supply and demand.

There is some debate whether or not carbon is the limiting factor for coral health and growth. My guess is that carbon dosing fosters the growth of microorganisms that feed corals and consume nutrients, rather than bacteria that consume nutrients.

Well i don't run carbon so would you consider running the skimmer at 0.5 duty, cutting water changes to 5% weekly and preventing algae growth a good initial approach to the problem?

I don't see a problem with cutting back on protein skimming hours, especially if you don't have nuisance algae problems or high nutrient levels. If the LPS that you want to focus on are night feeders like Acanthastrea & Lobophyllia then maybe skimming during the day will be better for SPS and not skimming at night will offer more available food for night feeding LPS.

What are your nitrate and phosphate levels now? While protein skimmers are very efficient at removing protein, they will allow heavy metals to accumulate. If your nutrient levels are above zero, it's possible that the LPS are adversely affected by heavy metal accumulation.

The other approach would be to maintain your filtration as is, and do more indirect feeding with Phytoplankton.

I thought about skimming in the day for that reason but I'm worried about oxygen levels dropping too low overnight. My powerheads slow down at night and my return is herbie style.

Those levels are not detectable with my test kits.

How low does your PH drop at night. Your tank is well stocked so there must be significant coral respiration at night that would add a lot of Co2. A reverse photoperiod refugium would keep your nightly dissolved oxygen rates high and balance PH if that in fact is an issue.

I have mixed feelings about cutting back flow at night. On one hand it replicates natural reef conditions and allows plankton to get around better at night, but on the other hand it may lower dissolved oxygen, make it harder to off-gas Co2, and higher flow may be better for feeding extended night feeders.

Whatever you are doing right to keep phosphate and nitrate at zero appears to be great for your SPS, and not so good for LPS. I would guess that it's the low nutrients and not high toxic metal concentrations that are limiting LPS success.

Rather than limit what you are doing right (nutrient reduction & export through protein skimming and water changes), I would increase nutrient import with Phytoplankton, rotifers and whatever you prefer to feed. I've read a few threads on RC about dosing phosphate and nitrate, but I think they should be added via food, not chemically.