Ratherbeflyen
Well-Known Member
In an attempt to save energy, and space both in my sump and power bar, I decided to build an algae scrubber using the water return from my Precision Marine skimmer. The first step was to test the removal if the gate valve on the outflow portion of the skimmer. All the gate valve does is restrict flow raising or lowing the volume of water in the skimmer chamber. Replacing the gate valve with an adjustable repair coupling and some longer pcv pipe has the same effect of raising or lowering the water height in the skimmer by raising or lowering the height of the outflow/drain pipe making for easy tuning.
A couple notes on replacing the gate valve with a taller drain pipe.
1. If the water flows "down" too far while still in the pipe, it will create a siphon that intermittently drains the entire skimmer before it sucks air, breaks the siphon and refills. It either needs to be a short run (I only have a 90 degree elbow) or have a vent to draw air and prevent a siphon.
2. Tuning of the skimmer is way easier without the gate valve. I was constantly adjusting the gave valve, and have only made a couple of small adjustments to the pvc drain in the last 6 months.
A successful test of the drain modification working, I built an acrylic box out of a combination of black and clear 6mm acrylic sized to the space available on my sump. I then added 2, 10 watt led chips on each side for a total of 40 watts.
The algae scrubber box sits on the top frame of a 75 gallon tank I repurposed as a sump. I built the sump to have the refugium section first, mechanical second, rubble and skimmer 3rd and return chamber 4th.
The water flows out of the skimmer through the algae scrubber and onto some filter floss. Previous algae scrubbers I've made were after the mechanical filter and algae would always break off the scrubber and end up in the pump or display tank. Especially after cleaning the screen. Being installed before the mechanical filter solved that problem.
For the screen holder, I didn't want an actual tight fitting that was hard to remove. So I used a piece of 2" pvc pipe with end caps that I cut down ~1/2". (not glued together for ease of cleaning.) There is a slot cut in the bottom that holds the screen made from clear knitting canvas and a 2" hole in the top where the skimmer drain just loosely slides in to. The 1" lip around the outside of the box captures any overflows or spills and directs the water back to the screen. In 6 months, I've never had a leak or spill. Though if it did, its all in or directly over my sump anyway. To clean the screen, I just shut off the skimmer and lift the drain line up. I can then easily move and remove the screen or whole scrubber for cleaning.
Day 1 of installation was on January 23.
February 1st.
February 9th.
February 18th.
March 2nd.
6 months in and I clean one side of the screen every 7-10 days.
My 220 gallon tank has been up for just over a year. My only filtration is algae with this scrubber and some cheato in the refugium, a skimmer, filter floss, and a little carbon in a media bag.
I have 2 tangs, 2 clowns, 8 cardinals, 3 anthias, a yellow clown goby, a blue damsel, 2 fire fish, a flame hawk, and a purple dottyback. I feed those 20 fish ~5 cubes of frozen food every day. With an API test kit, I've never had a detectable level of nitrate or phosphate. I'm completely sold on algae for natural filtration. I've said before and keep saying, I'll never set up another tank without one.
I made this post mostly because I've never seen anyone use a skimmer drain before. I've also heard of people using the display tank overflow drain, but I can't recall ever actually seeing an algae scrubber installed on the drain. If you're new to algae scrubbers, there are a lot of good threads here about building algae scrubbers that inspired me to build this. like this one, https://www.reef2reef.com/threads/building-your-own-algal-turf-scrubber-ats.541118/ . Hopefully this helps inspire someone else and I'll try to help answer questions if I can.
A couple notes on replacing the gate valve with a taller drain pipe.
1. If the water flows "down" too far while still in the pipe, it will create a siphon that intermittently drains the entire skimmer before it sucks air, breaks the siphon and refills. It either needs to be a short run (I only have a 90 degree elbow) or have a vent to draw air and prevent a siphon.
2. Tuning of the skimmer is way easier without the gate valve. I was constantly adjusting the gave valve, and have only made a couple of small adjustments to the pvc drain in the last 6 months.
A successful test of the drain modification working, I built an acrylic box out of a combination of black and clear 6mm acrylic sized to the space available on my sump. I then added 2, 10 watt led chips on each side for a total of 40 watts.
The algae scrubber box sits on the top frame of a 75 gallon tank I repurposed as a sump. I built the sump to have the refugium section first, mechanical second, rubble and skimmer 3rd and return chamber 4th.
The water flows out of the skimmer through the algae scrubber and onto some filter floss. Previous algae scrubbers I've made were after the mechanical filter and algae would always break off the scrubber and end up in the pump or display tank. Especially after cleaning the screen. Being installed before the mechanical filter solved that problem.
For the screen holder, I didn't want an actual tight fitting that was hard to remove. So I used a piece of 2" pvc pipe with end caps that I cut down ~1/2". (not glued together for ease of cleaning.) There is a slot cut in the bottom that holds the screen made from clear knitting canvas and a 2" hole in the top where the skimmer drain just loosely slides in to. The 1" lip around the outside of the box captures any overflows or spills and directs the water back to the screen. In 6 months, I've never had a leak or spill. Though if it did, its all in or directly over my sump anyway. To clean the screen, I just shut off the skimmer and lift the drain line up. I can then easily move and remove the screen or whole scrubber for cleaning.
Day 1 of installation was on January 23.
February 1st.
February 9th.
February 18th.
March 2nd.
6 months in and I clean one side of the screen every 7-10 days.
My 220 gallon tank has been up for just over a year. My only filtration is algae with this scrubber and some cheato in the refugium, a skimmer, filter floss, and a little carbon in a media bag.
I have 2 tangs, 2 clowns, 8 cardinals, 3 anthias, a yellow clown goby, a blue damsel, 2 fire fish, a flame hawk, and a purple dottyback. I feed those 20 fish ~5 cubes of frozen food every day. With an API test kit, I've never had a detectable level of nitrate or phosphate. I'm completely sold on algae for natural filtration. I've said before and keep saying, I'll never set up another tank without one.
I made this post mostly because I've never seen anyone use a skimmer drain before. I've also heard of people using the display tank overflow drain, but I can't recall ever actually seeing an algae scrubber installed on the drain. If you're new to algae scrubbers, there are a lot of good threads here about building algae scrubbers that inspired me to build this. like this one, https://www.reef2reef.com/threads/building-your-own-algal-turf-scrubber-ats.541118/ . Hopefully this helps inspire someone else and I'll try to help answer questions if I can.
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