CerMedia MarinePure Block Bio-Filter Media for Marine and Freshwater Aquariums, 8 by 8 by 4-Inch, white to off white

Bought the large brick as I have used MarinePure for years. I used 3cft of it in my koi pond shower and used it in multiple fresh water set ups as well. I ordered this for my reef tank and as expected it is a great biological filtration choice. It does its job due to its porous design however it doesn't handle rough shipping well. My brick came broken in half. It doesn't look great but it lost none of its function. I would buy this over and over again in figure set ups without a single concern.

I can't say enough about these bioplates. I saw these on Bulk Reef Supply in one of their video series and decided to try them on my next tank setup. I now am convinced that every tank should have these in the sump. I work in a LFS that services reef tanks. We have seen a dramatic drop in problems since adding these to tanks. We have begun to replace all blue bioball systems with the plates...its simply no match. The bioplate clearly has a greater surface area for bacteria to colonize to and effectively reduces nitrates due to the massive increase in biological filtration. Anyone looking to run a system with a minimalist type of aquascape should drop a 8x8x4 block in their sump. The only con is that the plates sometimes arrive cracked. Unless you are trying to use these in-sump standing up (like in a Vertex sump) then the crack doesn't cause issues. I used 1/3 of a cracked 8x8x1 plate in my personal Nuvo 38 and the other 2/3 in a client's 55gl. Both tanks saw a dramatic reduction in algae growth after 3 weeks (the time it probably took to colonize). I am no longer getting cyano in the nano tank which has plagued me for nearly a year and that was with weekly water changes (sometimes more). I have even added new fish to the tank finally.

I can't speak highly enough of these bio blocks. I already had one for my 150 gallon reef that has been in there for nearly 9 months with no issues. I ordered two more since I expanded the system to 270 (added frag tank volume with little-no live rock) gallons total and I can't wait to see how three perform. Please, for the love of God, don't pay attention to these reviews saying it crashed their tank or gave them issues. Yes, it's brittle because it's so porous so you have to be careful. Yes, you NEED to rinse it THOROUGHLY! I rinsed all of mine with RO/DI water in a 5 gallon bucket several times before placing them in the tank and never had any issues or saw any sort of cycle.

I bought this to use in my reef tank. I saw it on a BRS video and they showed how much water it held because of the pore network I was impressed. I put it in my sump in the refugium in a low flow area under a ball of cheato to keep it blocked from the light. I figured having the extra surface area for bacterial filtration couldn't hurt. My nitrates stay around 1ppm. This stuff is very very very delicate. If you squeeze it too hard you get little particles of it coming off in your hands. When I first got it I soaked it in RO water and gentle lifted it up and down to try and get as much loose stuff off as possible and did this with fresh RO two or three times until the water stayed pretty much clear. Basically place this in your sump somewhere you will not be hitting into it or pushing it around and just let it be. This is a great option if your going for a minimal rockscape in the display. I have one 8x8x4 block in the refugium and one 8x8x1 block between a set of bubble baffles on my 90 gallon setup. As far as the aluminum scares. I read all the threads on the forums before buying the blocks. I put them in May 1st.......I had a triton test done last year on 7/21/15 and my Al reading was 0.11ug/l This year 6/12/16 a month after the block was added the Al was 24.93 ug/l. NOTHING in my tank has had ANY ill effects since the addition of the blocks and my tank is loaded with sps.

I have used this product for years and I think it is a great product. So why the 1 star review. Just opened product to find that 1/10 of the block was nothing but crumbs in the bag. Purchased for my 3xl 900 Redsea 240 Gallon saltwater. May try another product next time because of this. There is usually some crumbs but this time it was so many I am disappointed. Oh well it is installed and I don't want to remove it now and return.

I really wanted the 1" thick block to put inbetween sump chambers. But noticing that the 4" block is basically the same volume as 4x the 1" thick blocks but for less than twice as much, I couldn't resist the value. So I ended up buying the 4" thick one and slicing a 1" slab out of it which I used for my intended purpose. The rest of it I just put in my refugium. I know however I may be negating the "anaerobic bacteria development" deep within the block but it was worth it to me. You still get a ton more surface area. It has defiantly helped keep my nitrates down.

The product was nicely packed on arrival. When handling it the first time while flushing with water, some parts of it did crumble. When I texted the company, they respond in less than 15mins explaining it. Just for that, I decide to keep the product, handling it with my palms with more finesse. Looking forward for it to do it’s magic.

Although this product is incredibly porous and makes theoretically great sense- this block is incredibly crumbly even when being handled with great care- upon rinsing the outer layer was falling off and even with the second rinse- ditto. It is supposed to be placed in a slow flow area of your sump- well, that is right before the last baffle and sponge that protect my last sump box with the return pump in it. I did place it and immediately could see a bunch of granules from the block on my course sponge - this makes me nervous for my return pump, but I will update on its chemical results and if its delicate nature becomes a problem.

tenia dudas al comprar por que vi que llegaban rotas pero ya mejoraron el empaque por que venia en una caja que dentro tenia otra caja y dentro de esta venia el producto con su empaque original, bien protegida excelente servicio y ya esta funcionando en mi acuario

Great product. Must for marine aquarium . I have seen many videos of abroad using it

Have a heavily overstocked aquarium with two of these. Never had any problems with water quality. Fantastic product, bit expensive though.

Delivered exactly as I expected. The product should be a great aid to my freshwater tank.

I feel it is the best for media bacteria, why I gave 4 star coz I received some small part is break, but anyway function still good. Otherwise I will give 5 star