Fluval flex 123L

Reefnoob97 · Aug 5, 2022

Hey all, I've just recently purchased a fluval flex 123L. After a bit of help/recommendations on a couple of things
1. Decent protein skimmers that won't be too harsh on the bank
2. Any filtration upgrades people can suggest
Any photos of set ups etc would also be appreciated
Thankyou

Bucs20fan · Aug 5, 2022

The Fluval PS1 is like 80 dollars and would be a fine skimmer that looks good on that tank. I would upgrade the light in time if you can. The filtration is just fine on that tank, a good ole sponge, some poly fiber, and some matrix from seachem, and youll be rocking and rolling. I would recommend adding more rock. Youll need probably 20-30 lbs of rock for that tank.

ScubaFish802 · Aug 5, 2022

Bucs20fan said:
The Fluval PS1 is like 80 dollars and would be a fine skimmer that looks good on that tank. I would upgrade the light in time if you can. The filtration is just fine on that tank, a good ole sponge, some poly fiber, and some matrix from seachem, and youll be rocking and rolling. I would recommend adding more rock. Youll need probably 20-30 lbs of rock for that tank.

The fluval PS1 is known to be a not great skimmer - check out the reviews on other flex threads and groups - specifically surrounding the never ending micro bubbles. Check out Icecap like the K1nano (pump is not super great longevity wise, but overall functionality will far exceed the ps1) or the newer neo (smaller but basically the exact same thing as the nano - a little smaller overall).

The sponges that come with the tank are not a great filtration method. Check out inTank Aquatics or 3Deep media baskets with some filter floss in the top.

I no longer have my flex 123l (have since moved to a reefer 250), but that setup ran great for a couple years.

Kasrift · Aug 17, 2022

Agreed, the sponges aren't ideal. They would be a mess to clean as well. The InTank media racks are what most people will go with. If you are on the budget side, then there are lots of people that just build their own. I'd highly recommend looking into how to block the lower vents to help with filtration and surface scum.

I'd second avoiding the PS1 skimmer. You'll just replace it anyways. I've been looking at replacing mine after having it awhile.

MrJago · Oct 27, 2022

Hi everyone.

I have been running a Fluval Flex 123L for approx 8 months now, but have had a problem with green hair algae from after the tank was cycled until now. I have upgraded the filter by changing out the stock filter sponge and replacing it with a media basket. I do not use a skimmer and I don't have a powerhead yet but have recently just ordered one (nero 5). Periodic water change are done along with cleaning of tank and equipment and water parameters are all fairly stable. Since using phosguard in a media bag for a few months now I have only been testing low levels of PO4.

My question is, how do I tackle this green hair algae problem? I know new tanks will go through blooms and maybe this is the case for me, or will the addition of a powerhead alone make a difference?

I don't really want to buy a protein skimmer as I will be upgrading to a bigger tank next year and therefore will need a protein skimmer to suit.

Kasrift · Oct 27, 2022

More clean up crew helps a ton. Also, with some patience, Microbacter clean works great when adding it to your routine. I added a tuxedo urchin and he chomps down on algae. I don't really see any snails in your picture.

I have the same tank and my clean up crew is: 3 turban snails, 5 astrea, 3 cerith, 4+ lightning dove snails, 2 margarita snails, 1 bumblebee snail, 5 nassarius snails, 1 turbo snail, 1 strawberry conch, 1 tiny blue legged hermit, 1 much larger electric blue hermit, 1 small red hermit, and 1 tuxedo urchin.

jimretr0 · Dec 16, 2022

MrJago said:
Hi everyone.

I have been running a Fluval Flex 123L for approx 8 months now, but have had a problem with green hair algae from after the tank was cycled until now. I have upgraded the filter by changing out the stock filter sponge and replacing it with a media basket. I do not use a skimmer and I don't have a powerhead yet but have recently just ordered one (nero 5). Periodic water change are done along with cleaning of tank and equipment and water parameters are all fairly stable. Since using phosguard in a media bag for a few months now I have only been testing low levels of PO4.

My question is, how do I tackle this green hair algae problem? I know new tanks will go through blooms and maybe this is the case for me, or will the addition of a powerhead alone make a difference?

I don't really want to buy a protein skimmer as I will be upgrading to a bigger tank next year and therefore will need a protein skimmer to suit.

I picked up some live rock that brought hair algae into my tank, I got rid with 5 cheap as chips black led hermit crabs and a algae blenny.
If any comes back they are on it before it's ever a problem.