DIY upgrade of existing skimmer to recirculating configuration

[drblank1]

I’ve had my Euro Reef CS 6-2 skimmer since 2005 (see pic below). It skims well as long as parameters/circumstances don't change in the tank. But being a one AC pump skimmer with only a riser pipe, it was limited in adjustments.

My skimming is very aggressive. I pull out 1 gallon of dirty lemonade colored skimmate daily. I do this as my water change method. I replace the skimmate with 1 gallon of new saltwater daily. But being this aggressive, if there is any little change in the ecosystem, the skimmer would go crazy and overflow. Obviously, I could back-off on the aggressiveness of my skimming, and it does work well, but the skimmate comes out more like a thick paste. Not much in-between dirty lemonade and a thick paste.

Over the last 2 years, I've tried various new under-$400 single-pump skimmers (both ac and dc) and was disappointed in their performance compared to my old Euro Reef. And comparing construction, they seemed like little toys compared to the Euro Reef. The ER is built like a tank. I always ended-up returning the new skimmer.

So I decide to try and increase the adjustability of the ER skimmer. I added an air valve to the airline. This helped a little but there is still an issue where if you reduced/restricted the amount of air volume going into the pump, the pump sent more water into skimmer. This causes air bubbles to be pushed out the exit pipe. The more the air is restricted, the more water is pumped into the skimmer and more air bubble exit the skimmer. Bottom line, air adjustment in this configuration is limited.

So I decided to bite-the-bullet and buy a new DC recirculating skimmer. They are expensive. As I researched and studied the new skimmers, I started thinking, “The designs of the recirculating skimmers aren't complicated. Why couldn’t I modify my skimmer to be a recirculating skimmer like the one’s I see for sale?” So I decided to try it. So I went out and bought some fittings and two uniseals.

Next post. Modification of the Euro-reef skimmer.

 

[drblank1]

Materials:

(1) 3/4" uniseal
(1) 1" uniseal
(2) 3/4" PVC elbows
(1) 1" female threaded to slip elbow
3/4" and 1" pvc pipe

Tools:

1.25" and 1.75" Hole saws
Drill

Step 1 - Create the return/source for the needle wheel skimmer.

The water intake to the air venturi is an odd size but 3/4" pipe loosely fits inside the intake. I wrapped teflon tape around the pipe and shoved it in the intake. Good enough for now until I glue everything together. I dry-fit the pipes and lined-up where the hold should be drilled. Drilled the 1.25" hole and insert the uniseal.

Step 2 - Create an input for the feed pump

I just happen to have a Motion 1.8k DC pump and decided I would use it to feed tank water to the skimmer. I like the idea of being able to control the amount of water going through the skimmer. The pump has a 1" fitting so I would need to saw a 1.75" hole to fit the 1" uniseal. I decide saw the hole right at 8" up the body as this is the top of the fixed water level of the sump chamber where the skimmer sits. The water exits the bottom of the skimmer so I want it to travel down through the bubbles to increase contact time. I sawed the hole and inserted the uniseal. I wanted to keep things compact as its already a sight fit in the sump. So I placed the hole so the feed pump is suspended above the new piping. The pump weighs next to nothing.

Step 3 - Assemble the skimmer

Everything went together well. For now, I dry-fitted the piping. Once I use the new configuration for a few days to a week and all is good, I'll glue the piping.

Next post - use, test, and post results.

 

[drblank1]

I put the skimmer back into service Monday evening.

I set the feed pump to 25%, then turned on the needle wheel pump and adjusted the riser pipe to bring the foam to the top of the skimmer. Then I adjusted the air valve about half way to create a bit of drier bubbles.
Within a couple of minutes, this is what I got.

Within about 30 minutes, I had this in my skimmer cup.

The next morning (about 12 hours later), I had this in my skimmate reservoir (also DIY).

This morning (about 36 hours later), I had this:

That is a gallon container. I am blown away. I could never get this kind of results with a 1 pump skimmer. Skimmate was always a thick paste or liquid lemonade.

Total cost? Less $18. I looked up the 1.8k pump and its sold for ~ $110.

IMO, the equivalent to this skimmer (and what I was going to purchase) is the Reef Octopus Classic 150EXT 6” Recirculating Protein Skimmer which goes for $440. I saved over $400 by making this modification. The feed pump is still needed for the 150EXT.

The next mod will be to replace the riser pipe with a gate valve. I might be able to get to that in the next couple of weeks. But for now, I am going to experiment with the feed pump speed and air valve to see what kind of different results I get.

I'll post the result when I have time to experiment.

 

[drblank1]

I wanted to add a 1 1/2 inch gate valve to the riser pipe but decided NOT to do it. The riser pipe adjustment is doing just fine AND gate valves are ridiculously expensive thanks to inflation.

I've started experimenting with skimmer adjustments. I kept all adjustments the same but increased the feed pump from 25% to 30% for the past week. No noticeable difference in skimmate collection. Up next is to make a more significant increase in the feed pump from 35% to 50%. Will provide an update in another week.

 

[Snoopy 67]

 

[drblank1]

An update: I upped the feed pump to 50% and the skimmate was a bit lighter. but collected about the same rate. Then I fully opened the air valve and the skimmate collected faster. Still experimenting with different settings.

Since I've modified the skimmer, the best benefit is I have had ZERO overflow/skimmer going crazy events. I used to have multiple overflows every week. I am sold on recirculating skimmers.