New Tank: When to add Marine Pure Block?

reelss · Jan 28, 2018

Hi folks,

I am just about ready to start cycling a new set up. I have about 100 lbs of dry rock in a 120 gallon set up. I also have a 8x8x4 Marine Pure block for my fuge. Is it ok to have the block in there during cycling? Or should it be added once the cycle is complete?

B-ridge · Jan 28, 2018

Following. Curious to others opinions

cpschult · Jan 28, 2018

Add it at the beginning. You can start colonizing bacteria on it. If you add it after the cycle it will end up colonizing then. No reason to wait.

Randy Holmes-Farley · Jan 28, 2018

Is never a choice? [emoji23][emoji23]

ronl · Jan 28, 2018

Randy Holmes-Farley said:
Is never a choice? [emoji23][emoji23]

I would love to hear more of your thoughts on this. Thanks

B-ridge · Jan 28, 2018

Not sure but I don’t think he’s in favor of the blocks. I would like to hear more on his thoughts also

5altkreep · Jan 28, 2018

Ive seen alot of mention of the blocks possibly leaching aluminum.
Disclaimer : I am not claiming that to be true or false, and I have no personal experience with them.

saltyhog · Jan 28, 2018

This is my Triton results when I had 2 Marine Pure blocks in my sump. I can't say there was any issue with the aluminum level but then again I don't know what my tank would have looked like without them. I replaced mine with Brightwell bricks.

B-ridge · Jan 28, 2018

Are the brightwell supposed to be better or something? I was under the impression they both did kinda the same thing

saltyhog · Jan 28, 2018

B-ridge said:
Are the brightwell supposed to be better or something? I was under the impression they both did kinda the same thing

Brightwell actually has a couple of different bricks. One of them is impregnated with sulfur to aid in denitrification.

As far as I know, they haven't been associated with aluminum leaching.

Idoc · Jan 28, 2018

100lb dry rock? Are you sure you will even need a Marine Pure block? You are already going to have so much surface area for bacteria to colonize! I guess more can't hurt, though.

VR28man · Jan 29, 2018

ronl said:
I would love to hear more of your thoughts on this. Thanks

See, for instance, here:

https://www.reef2reef.com/threads/anaerobic-zone-question.351443/#post-4371981

Idoc said:
100lb dry rock? Are you sure you will even need a Marine Pure block? You are already going to have so much surface area for bacteria to colonize! I guess more can't hurt, though.

Agreed with this. If you have that much rock, I think the only reason to add something like a marine pure is if you were unsatisfied with the way it denitrifies. And the only way you would really know that is after a slow cycle of about three months.

Randy Holmes-Farley · Jan 29, 2018

ronl said:
I would love to hear more of your thoughts on this. Thanks

Too low of nitrate is not an uncommon problem, is worse than elevated nitrate, and Marine Pure blocks may well drive it too low.

I also do not care for the potentially released aluminum.

Randy Holmes-Farley · Jan 29, 2018

saltyhog said:
Brightwell actually has a couple of different bricks. One of them is impregnated with sulfur to aid in denitrification.

As far as I know, they haven't been associated with aluminum leaching.

The normal Brightwell Dimpled Brick released aluuminum and silicate in this test:

https://www.reef2reef.com/threads/h...-leach-lets-guess.247034/page-20#post-3929299

jorahx · Jan 29, 2018

Is there proof that the marine pure blocks release aluminum? I've read both sides to the story.

Randy Holmes-Farley · Jan 29, 2018

jorahx said:
Is there proof that the marine pure blocks release aluminum? I've read both sides to the story.

Not sure what "other side" there might be aside from a manufacturer making claims they probably never even tested (and certainly never showed). Manufacturers have long fought chemical reality by making simplistic claims that aluminum oxide and other ceramics were "insoluble" so cannot release anything.

It is certainly the case that lots of people use the Marine Pure product just fine, and do not apparently have sufficient aluminum released to be a problem in their tank (maybe they export it faster than others). That is by far the most common case: no apparent problem.

But the majority of people that I have seen results for who are using it do have released aluminum when they look with an appropriate method.

VR28man · Jan 29, 2018

Randy Holmes-Farley said:
Not sure what "other side" there might be aside from a manufacturer making claims they probably never even tested (and certainly never showed). Manufacturers have long fought chemical reality by making simplistic claims that aluminum oxide and other ceramics were "insoluble" so cannot release anything.

It seems that they did do, and show, an admittedly limited test last year. Sending their samples to triton.

http://cermedia.com/blog.php?p=142

Beyond the anecdotal size (ie not a big enough sample, something rampant in all categories of tests for reef hobby techniques and products), what do you find deficient about it?

(Full disclosure: i use an mp block, though not in the way inshoild have. That being said, if i was persuaded their claims were false, i would look to dump it)

Randy Holmes-Farley · Jan 29, 2018

VR28man said:
It seems that they did do, and show, an admittedly limited test last year. Sending their samples to triton.

http://cermedia.com/blog.php?p=142

Beyond the anecdotal (ie not a big enough sample group, something rampant in all categories of reef techniques and products), what do you find deficient about it?

(Full disclosure: i use an mp block, though not in the way inshoild have. That being said, if i was persuaded their claims were false, i would look to dump it)

Thank you very much for posting that. I had not seen such a study.

FWIW, it is an unusual study (IMO). They started with water that was already high in aluminum. In fact, the starting aluminum concentration (67.69 ug/L) is already above the published solubility limit of aluminum in seawater (see scientific paper below). How could any more dissolve? They probably should have started with a more typical reef aquarium water, which in the absence of white media of various sorts, usually has little to no aluminum detected in Triton tests.

When you add soluble aluminum to seawater, only about 2 uM (54 ug/L) will actually remain in solution and any more will precipitate as aluminum hydroxide (see the table in the scientific paper linked below) .

Aluminum hydroxide’s solubility and the forms of dissolved aluminum’s occurrence in seawater
Oceanology April 2011, Volume 51, Issue 2, pp 231–234
https://istina.msu.ru/media/publications/article/b34/6a0/8552301/Oceanology-2011-2.pdf

saltyhog · Jan 29, 2018

Randy Holmes-Farley said:
The normal Brightwell Dimpled Brick released aluuminum and silicate in this test:

https://www.reef2reef.com/threads/h...-leach-lets-guess.247034/page-20#post-3929299

Thanks Randy. I know that's anecdotal and a series of one but it does cause concern. Interestingly my aluminum level with Marine Pure peaked at 39. I was running GFO then but I'm not now. I'll send a Triton test off and see what it shows.