Automatic Intermittent feeding system - remote sump systems


Premium Member
Looking around at various ideas for automated continuous (actually intermittent) feeding system ideas. Obviously, on a reef, feeding is not once a day at 5 pm when the owner happens to come home - it is more or less continuous - probably important for fish such as tangs, and especially for non photosynthetic inverts.

A few problems
- if you put the food into the sump before the main pump, it can get mashed up - I have seen some studies where they found extensive >90% destruction with a main return pump.

- Refrigeration - if you want this to need maintenance only say, once a week, you have to refrigerate many choices for food

- Dead space in tubing - if you do refrigerate, you can only use short tubing distances outside the refrigerator - since because of the very small volumes of feeding, it will spend quite a bit of time sitting in the dead space of the tube before going into the tank
- If you have a remote sump system, then you are a very long way away from the tank

After seeing quite a few ideas on the web, I put together an idea for a small system -

1. Get a very small fridge - there are lots of these now - car fridges etc - small enough for a few cans of soda - not as big as traditional small fridge

2. Use a dual peristaltic pump system - pump 1 goes on first, and delivers a small volume of the concentrated food, and then pump 2 goes on for a volume sufficient to flush the line. Pump 2 could draw its water from the sump or refugium as needed

3. The feed goes into the main return line after the return pump - this would work, since peristaltic pumps do not permit backflow, and are fine pumping into a high pressure area

What do you think? I am inherently lazy and like the idea of automating things. It has always struck me that it is weirdly unnatural to feed our little friends a big lump of food once a day. (I will try to paste the diagram below)



In Memoriam
Why not just draw water up from the display tank with that pump, feed it into the fridge's food supply and let it run for 15 minutes? The warmer water would melt some of it off the stash, sending it into the tank.

The only drawback I can think of is if you are trying to drop a specific amount of food each session. If you could modify an icecube tray to drop the daily cube or cubes into a dish, then the warmer water flowing over the food would dissolve it and send it down to the tank.

I think the daily amount of food is going to be the hurdle, unless you don't mind melting off a little bit of a large blob of food every 6 hours or so.

If this is liquid foods like Phyto, rotifers, etc... you still have the daily dose itself to contend with. Do you have any thoughts on that process?


Premium Member
Thanks, Mark
My main tank is on the main floor of my house, with the sump in the basement - no place to add on a feeder near the main tank.

My thought was to mix up a bunch of stuff in a container every few days, and have small amounts of it dripped in every hour. I would use a peristaltic pump with the ability to give small amounts accurately.

I have seen a few different mixes people use - some plankton, amino acids, and some frozen food. Something like 5 ml of liquid followed by 20 or more ml of saltwater.

The saltwater for the flush could come from anywhere in the system - in my case because of odd geometry in my sump room I might take it from a frag tank, and then just plumb the output into a nipple in the return line.


In Memoriam
That was an incredible thread. I even learned some new German reefing-terms, which until now I've never even tried to grasp. :D

His creativity was admirable, with some fascinating turns when things didn't work out.

So I've been thinking more about your feeding system. Here's what I've come up with.

Food should be in a funnel shaped cone. Ideally, it would be best if the food stayed frozen. Then tank water could trickle into the fridge, pouring over the frozen food. Little bits would thaw and run off into the funnel, down the tube and into the tank (or sump near the return pump).

The issue I see is the tubing with the water. When the pump turns off (I was thinking about the Aqua Lifter because it is quiet, uses little electricty, and moves about 3g of water per hour), the water in the tube in the fridge would freeze. The next time it had to turn on, it wouldn't be able to let new water pass, I fear.

If it isn't frozen food, but really is only a refrigerator, the food would melt in that environment (40F) so you'd have mush in no time. How long the mush is good is something you need to determine. How much enters the drain to the tank / sump is the next hurdle. Do you want a specific amount of water to flush into the system to keep it clean and avoid any clogs?


Premium Member
It is an amazing thread - and quite a tank.

I agree a funnel shape of some kind would be needed - maybe IV bags and IV tubing would work - cut open the bag top, and suspend it in something (top half of a 2 litre pop bottle upside down?).
I had thought of non-frozen food in a liquid. It could contain melted frozen mysis or brine shrimp, plus plankton etc - not sure how long it would last in a fridge at about 40 deg F - at least 5 days I would think.
For a pump, I was thinking of one of these type - -
they are very precise, will pump against pressure, and will not allow any backflow. I would try to keep the distance of tubing for pump 1 as short as possible. Maybe 10 doses of 2 ml per day? or vary according to the mixture.

This is kind of a funny hobby - there are about 10 zillion posts debating tiny details on skimmers - most of which are probably just fine - but people get fantastically loyal, and completely obsessed - over differences that probably don't matter at all - but then, something as blatantly obviously wrong as feeding just once a day gets very little attention - I had seen some of your earlier posts on this, and knew you had thought about it.

If I recall correctly (can't find the old posts at the moment) you used a contraption with a wine cooler, I believe? Do you still use it?



In Memoriam
No, I didn't build one. However, Evan did make a Pappone Reactor that used a small box, a tiny pump, and an airstone. He wanted to use it to trickle in food, and also use it when dosing other stuff (Amino Acids, Vitamin C, etc). It didn't work as well as he hoped.

There was a very good article about feeding often for a species tank that you might want to peruse:
Report on a Successful Husbandry Method for a General Azooxanthellate Reef System including Dendronephthya


New member
I remember reading a thread like you mention - a wine chiller, IV bag, dosing pump. I was looking for it the other day with no success, funny timing to see your thread. I remember the OP said the chiller could freeze the liquid food if not careful. I believe they used liquid foods like rotifeast?

I like your idea with the flush-water via a second pump. I wonder though if everything would need to be refrigerated right up to that node where pump 1 and pump 2 discharges meet?


part time superhero
Its an interesting concept that could have very nice benefits and disastrous consequences should something go wrong.


In Memoriam
Steve continues to impress me with his ideas. I wouldn't have guessed that equipment would function well in a 40F environment, like the inside of a fridge. Thanks for the link, Nathan.


Premium Member
Steve Weast has a brilliant solution for vodka, phyto, etc.: Look half-way down the page
Thanks for the suggestion - this is a great thread - have to study it.

Yes, it would be a concern if the contents in the dead-space of #1 sat there long enough to spoil. Would have to calculate the volume vs flow rate to figure out how long it would be in the exposed part of the tubing. Or, just put the doser in the fridge.

A good peristaltic pump is very robust - and with proper choice of the tubing exposed to the pump wheel, they can operate a long time.

We use these in the hospital for a lot of things - and they last for years and years. I once got one that was being thrown out - over 20 years old - and I used it for a further 7 or 8 years, and really abused it.


New member
<a href=showthread.php?s=&postid=15441628#post15441628 target=_blank>Originally posted</a> by JohnM99
Where did you buy it? I don't see it on the GeoReef site

I bought it used from a member here... but I also PM'ed GEO about it. It's actually a really simple concept once you see how it works and you could even build one yourself out of 3 plastic containers stacked on top of each other.