Anyone having trouble with RO carbon blocks being slightly too short?

fcmatt · Jun 12, 2024

Hello everyone,

I have been using a Coralife Pure-Flo II RO/DI system for years. A decade plus even. I swap out membranes every 5 years and naturally I have to replace my sediment/carbon filters on a regular basis.

Recently I ordered a new standard 10" carbon block from a vendor. Once installed I could literally see it spin slowly when I bumped the canister. Thinking I got a bad one I ordered another from a different vendor. Same result. It simply does not make good contact with the top and bottom of the canister. I just do not see those little round indentations in the rubber o-ring they have at the top and bottom.

Now the sediment filter is fine. It makes solid contact. I compare the length of each and the sediment filter is slightly longer by approx 1/8". My temporary solution was to rip out the rubber ring on the old carbon block and double it up on the newly installed carbon block. Now it fits great. No spinning and water is forced through it.

Is anyone else running into this? Never had this happen in years and years of replacement. I even swapped filters around as a way to troubleshoot it. Same issue on the other side with a different canister. I mean installing these things is not rocket science. They just seem shorter all of a sudden by a tiny bit.

Any advice is appreciated. The only solution I can think of is to just keep trying different brands until I find one that is actually as long as the sediment filter.

exnisstech · Jun 13, 2024

Maybe try @Buckeye Hydro

Malcontent · Jun 13, 2024

Shrinkflation?

Buckeye Hydro · Jun 13, 2024

fcmatt said:
Hello everyone,

I have been using a Coralife Pure-Flo II RO/DI system for years. A decade plus even. I swap out membranes every 5 years and naturally I have to replace my sediment/carbon filters on a regular basis.

Recently I ordered a new standard 10" carbon block from a vendor. Once installed I could literally see it spin slowly when I bumped the canister. Thinking I got a bad one I ordered another from a different vendor. Same result. It simply does not make good contact with the top and bottom of the canister. I just do not see those little round indentations in the rubber o-ring they have at the top and bottom.

Now the sediment filter is fine. It makes solid contact. I compare the length of each and the sediment filter is slightly longer by approx 1/8". My temporary solution was to rip out the rubber ring on the old carbon block and double it up on the newly installed carbon block. Now it fits great. No spinning and water is forced through it.

Is anyone else running into this? Never had this happen in years and years of replacement. I even swapped filters around as a way to troubleshoot it. Same issue on the other side with a different canister. I mean installing these things is not rocket science. They just seem shorter all of a sudden by a tiny bit.

Any advice is appreciated. The only solution I can think of is to just keep trying different brands until I find one that is actually as long as the sediment filter.

Those circular indentions in the top and bottom gaskets are made by the "knife edge seals" in the bottom of the sump and the lid. If there is indication that the seals are not being made, then you'll get water bypassing the filter.
No need to shoot in the dark here. Our filters will fit. Been selling the same brand of carbon blocks into the reefing market for over 20 years.

fcmatt · Jun 13, 2024

Buckeye,

When you compare the length of your sediment filters and carbon filters are they the same exact length for the 10 inch models? Even 1/8" difference can be enough for contact to be poor.

I guess the next time people order take a look at the length. Often the sediment filter is slightly longer but it was never a problem until now.

Part of me wonders is if my RO/DI system is just getting old. It was manufactured so long ago my canisters are just slightly longer but I have no idea about that. I thought it was all standardized decades ago.

I am pretty sure I am not doing anything wrong. And yes if they do not make solid contact they pretty much do not work. Water will take the path of least resistance in this application. Once used your blocks should have very obvious indentations in them from the "knife edge seals". I am not talking super deep indentations but quite obvious though.

I am not even sure most users even know to look for that solid contact if they are newer to the hobby or not observant each and every time they change them out. They just assume that is how it is supposed to be.

I will gladly give you a try. I normally order sediment/carbon blocks and DI resin all together on a single order. I imagine you sell all three.