HydrofarmActive Aqua AS4RD Round Air Stone, 4 Inch

You're going to need a good pump to get the most out of these stones. I small 6 amp isn't going to cut it, Make sure you have a decent pump and you will be fine. . Also the suction cups don't don't stick very well to the bottom my my buckets , maybe its the nutrients I'm using or the temp of the water, but I just wanted to toss that out there. You may have to check them from time to time to make sure they didn't disconnect is all.Other than that they are pretty well made, not to heavy, but they don't feel like junk in your hand either. Nice bubbles, again with the right pump.

I needed a large pond stone for a relatively small fish pond (50 sqft x 2 feet deep). This fit the bill perfectly. It is sufficiently weighted that it stays put on the bottom of the pond and has sufficient area that the required driving pressure is negligible compared to the hydrostatic pressure required to drive air into a 2 foot deep pond. Note that the inlet port is for 3/8 ID tubing, so an adapter is required if you use an aquarium style air pump with the regular tubing. I'm driving the stone with nothing more than a tetra Whisper AP 150 and this really gets the water moving around. I suspect that the 6" stone would probably work just as well.

It worked well for half a season. I was a little rough with it. I used it in a water filled 55 gallon drum to make probiotic fertilizer for my garden. Worked great with a big pump only it was too much air. and I needed more outlets. eventualy within the 2nd month the middle part got a little loose but its probably because I was throwing it in. I would buy it again. I probably wil. it is the best made for the price. next time maybe Ill just screw it to the bottom of the barrel, which will stop it from getting banged around. anyway If you found my review helpful maybe you could let me know by clicking yes. Thanks

Bought two of these, had to return one because the epoxy on the outer edge was not completely sealed which resulted in the air leaking out in one big bubble. Not great. Returned it to amazon, they sent out a replacement and the replacement was fine. Based off a visual analysis, I'm not sure how long either of these is going to last BUT, I will say that they put out a good amount of bubbles and over a large area.For DWC they seem to be doing the job just fine. However, as with all the stuff I bought from Hydrofarm -- quality is suspect.

I am using one of these in the bottom of a General Hydroponics water farm. It is heavy so it won't float and the bubbles are very small which is important to increase the dissolved oxygen. I have been very happy with the product it works just as you would think. I am so happy I plan on buying a larger model for a Compost Tea brewer I plan on making. It is expensive, but you get what you pay for!

I bought four of these for my minnow bait station. The stones work well and I am able to clean them with a wire brush and refresh them. The problem is that the small 1/8" barbed connection is fragile. Two of the four I own broke after one season of use. Just removing the plastic tube is enough to snap them off. I had to fix by drilling and tapping a new 1/4 thread and installing a brass fitting. I have seen this comment on other reviews as well. The manufacture needs to improve the design of the inlet fitting.

the pressure really makes water look like it's boiling. we bought two.It uses a larger diameter hose. information really should be put on box. even retailer stuffs a note inside, hint, hint.this is what we bought to go with it;Inside 5/16" (8mm) 30 Ft PVC Clear Tubing Flexible Air Water Delivery Hose Airlinehttps://www.amazon.com/gp/product/B00T4IF3MY/ref=ppx_yo_dt_b_asin_title_o00_s01?ie=UTF8&psc=1**2020after 4 years of 24/7, these finally gave out. the bottom plate separated. I'd call that excellent service!we just ordered a 3rd set for the next few years in our 750 gallon water tank for aquaponics system.

I purchased two. One came intact and is working successfully. The other had the nipple on the left broken off and for the few bucks it cost, I didn't send it back or complain. It would cost them a few cents more to manufacture the nipple out of metal as it seems to be shown here, but they don't. You get what you pay for....a cheap product that you have to be very careful with.