Cryptic refugia
I am setting up a cryptic refugium. It will be part of the sump. The sump itself without the dividers is 28"x28"x14"H. I want to put 5-6 min. of seafloor aragonite 1-2mm plus some live rock. For lighting I have a standard NO fluorescent (blue). My thinking for this is to create a DSB and NNR. I Hope the live rock will inoculate the sand with worms and copepods and the likes. On a chance that any sponges survived of the rock it could grow and help in filtering the water.
Plus since it is a low light refugium it might be what they need. Is this a good plan? What kind a flow will be needed and what do the
sponge eat? DOC? This is for a 175 gal. reef.
<Sounds fine, sponges can utilize dissolved non-biological nutrients, but mainly feed on plankton of various sorts... likely don't require "extra" feeding. 2,3,4 volumes per hour for flow rate is about right. Bob Fenner>
I am eternally grateful.
Stephan

Breaking in with Live Rock
Dear Bob,
<Diane>
Thank you for your help. I purchased a small package of cubes of frozen food to feed the crabs and sponges. I believe it was too large for the sponges, so will try phytoplankton in a couple of days.
<Try running some of these cubes in a blender with a bit of seawater... and applying this blend (can be re-frozen) with a turkey baster or such... with your filter pumps, skimmer turned off for fifteen-twenty minutes...>
Nitrate and Ammonia are nearing zero. Two small crabs were found dead in bottom of tank, but two large and a small are still hanging in there. I think that the larger crabs may have eaten the smaller ones 
<Typical>
because when I removed the shells from the tank, they were empty... no meat, so to speak. That is why I purchased the frozen food.
I love the web site and am reading the Conscientious Marine Aquarist. I was able to borrow it from my local library, which is good because of the expense in beginning this wonderful hobby.
Again, your time and expertise has been appreciated... and quite helpful. Be chatting with you again in the near future I am certain.
Diane
<Indeed. Bob Fenner>

Encrusting Sponge?
Here's a third try at this. I think my previous e-mails have disappeared into the "ether". I am copying more addresses so perhaps one will get the mail. I have not received any messages about bounces at the wetwebmedia.com address. Perhaps some firewall or other security setting is eating e-mails.
Henry
<Not sure what is going on, but we have suspected that there maybe a problem. Just that none of our internal communication between WWM crew members has experienced any problems and we have sent several test emails and all have showed up. Today all three of your messages came through no problem, but I do not recall seeing any of them previously. Very strange indeed. -Steven Pro>
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Hi!
Last Friday I got 75 lbs of Florida aquacultured live rock and 120 lbs of live sand. My tank has now cycled and there is a lot of life on the rocks that I'd like to try to keep for the long term, if possible. In particular, there is this bright orange growth that seems to be some kind of sponge. Do you have any advice on what I can do to care for it?
<Not much written on sponges. I did get a chance to leaf through a prerelease copy of Steve Tyree's book on sponges when Bob was at my housing and editing it. It seemed nice enough for a early self-published work from the little I saw. Sponges are filter feeders and need dissolved organics. Feed your fish regularly and experiment with some of the phytoplankton products on the market. Buy fresh and follow the directions explicitly or they are nearly useless. See if you cannot track down something written by Rob Toonen on their use.>
Attached is a picture of some of the growth. To the left is another rock that has a similar life form but it is a burgundy color, just a little darker than the pink coralline algae. I assume it is something similar to the orange "stuff" and would need similar care. There is some similar growth on other rocks that is more of a drab yellow color. Also, would you have a source for live Mysid shrimp and copepods that I can purchase to place in the tank?
<I know I saw one of the various e-tailers selling packages of pods, mysis, spaghetti worms, etc. Try Inland, Indo-Pacific, etc.>
There may already be some amphipods in the sand but I haven't seen them yet and I want to get a colony started. Thanks for your help. -Henry
<You are welcome. -Steven Pro>

Re: Tree Sponge
For feeding, in the past I have been providing a frozen food from Ocean Nutrition called "invert food" that contains Zooplankton/Phytoplankton mixture. My LFS says this food is no longer available, so I have been stirring the sand bed once per week creating a mini-storm. 
<this is a much better feeding strategy for filter feeders... please continue>
Recently I found "DT's live Phytoplankton" and have been feeding this once or twice per week, and still stirring up the sand once per week. 
<OK>
Is the 8 months with no deterioration a sign that I am on the right track, or does this sponge last for a year then fade away from starvation? 
<the latter for most my friend. Sponges do not lose weight apparently like humans do. Still, you might succeed... more time is necessary>
Would you suggest other foods to feed? I have had a silver gorgonian for about 1 year and I figured they both would benefit from the sand stirs and plankton feeding. 
<the silver gorgonian is likely photosynthetic (dirty/ off-colored polyps? Not pure white right?) and can easily live for decades with proper care in captivity>
BTW I have a Red Sea Berlin skimmer that works O.K. on my 125G, 
<sorry to hear it>
it pulls about 1/3 cup per week of very dark liquid out of my tank. 
<not even remotely adequate, but if you are not having problems with nuisance algae, do regular water changes and tend to keep aposymbiotic creatures (non-photosynthetic) then it is just as well>
From my reading a good skimmer should do this daily, 
< a full cup daily should be easy... hardcore reefers/skimmers can draw more than a cup daily with well designed skimmers. Very high water quality here>
maybe the poor skimming is inadvertently contributing to my success with this sponge? 
<exactly my friend. Now do yourself a favor and be sure to stick with a them in the tank... either photosynthetic corals or non-photosynthetic animals. If you try to do both... one is sure to die. Yes, it may live a year or two... but this is sad compared to the natural lifespan of many decades (if not over 100yrs) for many>
Thanks,  Larry
<best regards, Anthony>