Blue Diamond ET 120 Septic or Pond Linear Diaphragm Air Pump

I bought this to replace a Gast pump (rocker piston aerator pump) that served me well for many years. I chose this because the Gast pump, although very good, was also very noisy. I placed this in a bench housing on the pond dock and coverd it with a large aluminium duct piece opened ,to shelter it from rain. You can hardly hear the pump and the amount of air it moved was considerably better than the Gast pump. I have had it for 3 weeks and am very happy with it. I have a similar smaller diaphragm pump for my Koi pond and it has lasted me for over 5 years. It is very easy to rebuild these diaphragm pumps and they work 24/7 for over a year before you need to replace the diaphragm. The rebuilding kit for the Gast pumps are expensive. I am thinking of buying a second one. Very impressed, and I would recommend this pump without reservations. Additional Information: It is now August 2020. Fourteen months after purchase. The pump has worked 24/7 and is still going strong. Just a little more noisy, still less than the Gast pumps. Just ordered the complete rebuilding kit $53 , shipping included. I am going to change the diaphragm before it breaks down. VERY DEPENDABLE pump, and my pond looks great.

We’ve been using this pump in our pond for a couple years and it works great. Well built, good power on the pump, and good value.

Love this awesome pump. After having to Replace my septic aerator pump 2 times in 10 years @ 500.00 a pop for a rebuild motor I decided to try this little guy for 1/2 the price. WOW.....What a difference ! Great little pump, low motor noise, strong air , and super easy to install! Great on my wallet too!

2d update: even the replacement diaphragms broke after 30 days- something is causing the unit to overheat and melt or break the diaphragms. I would definitely not buy this again, especially at a high cost. Update: in addition to the problem below, both diaphragms broke in year after 2 year warranty ended. Well, apparently they know this is going to happen. They include replacement diaphragms for you to put in. So I installed them however the flow of air is probably 1/3 what it was after the diaphragms have been installed. Either due to overheating or other issues after the diaphragm broke. This is a lot of money to spend just get two years out of it. I would say this is not a quality device that you can count on and maintenance every two years even if it would continue to work is way too often especially if you’re using it in a septic tank. I am using it as a pond bubbler so it should be in water that is far less caustic, but still doesn’t last. My two stars have just been dropped to one star because of the poor value for the money. And no, the seller nor the manufacturer never contacted me. I purchased this based on the specification shown including "This pump comes complete with a 1/2" ID bronze fitting" -.as the photo attached shows this is a 3/8 not half inch port. As a result my wasted additional cost for half inch ID weighted line and the benefit of a half inch hose is completely lost. This is a big deal for anyone who wants to make sure that they do not over pressure their system to get it to last longer and to produce more air. This appears also to be a misstatement by the manufacture as well. There was another fitting that was supposed to be included that was also a “straight fitting” but that was not included. Rather a 90° Rubber fitting, which is not a screw in fitting but has to be clamped on was included but unfortunately it is not designed to be easily used for a half inch outside dimension pipe. It is possible to force it, but I do not think this is the best solution as a 90° fitting also reduces the pressure and creates to potential default points. Bottom line it’s a 3/8 inch not a half inch screw fitting. I will update with the response from the seller, but be aware this is definitely not a half inch ID system, and the screw fitting provided is intended to use 3/8” Id hose. No response from the seller or manufacturer as of third day. Neither Amazon the manufacturer nor the seller have responded to this review or my specific communication regarding this problem.

We are using this to push two Rootscape Large Pond aerators. The unit was installed a couple months ago and has operated flawlessly. More than enough flow for the two aerators. There were some issues with the unit shutting down because of excessive heat but that was solved by building a permanent insulated home for the pump. No issues in hot or sub freezing temperatures since.

Pump is just what we needed. Pretty quiet, powerful, not too noisy....but it did not come with the hose coupler AND it is not really 1/2 inch more like 3/8th. We ended up attaching a hose OVER the air output. (1/2 inch I think) More airflow but it was a huge hassle and wasted days trying to buy/find that attachment. Also contacted amazon twice about this and...nada. I only buy from amazon now if I have to or I know exactly what it is I'm ordering and from who. Otherwise its pretty hit and miss.

We are using it to recover our septic system's leach lines- it takes time, but we are already seeing results. This little pump works it's heart out! if you are looking for bubbles, this is the system! we connected to 1" pvc lines and the amount of air it moves is amazing... it's housed inside a house with a wire back to allow it to draw cool air and stay out of the weather. We expect it to last for some time to come

Been working about 5 months straight as a pond aerator and no problems