Reef Ceramics

[Hobster]

With the use of Oyster shells in your mix, have you tested for increased phosphates in the water??

[mr.wilson]

Originally posted by Hobster
With the use of Oyster shells in your mix, have you tested for increased phosphates in the water??

No more phosphate than any other calcareous media (sand or rock). Phosphate will be adsorbed into the shell structure in your tank, converting inorganic phosphate to organophosphates. Iron-based phosphate removers will remove the organophosphates.

You could spray the shell with a weak acid if it tests for significant phosphates. Oyster shell contains some silate, but not enough to leach into the water.

Here's a link to the benefits of the shell matrix.
http://www.gvnr.com/79/2.htm
http://aiche.confex.com/aiche/2006/t...ram/P53148.HTM
http://cat.inist.fr/?aModele=afficheN&cpsidt=16915754

[beareef19]

Mr Wilson
The info in those links would suggest that the shell is a good phosphate absorber, is this correct? If so why hasnt this been used is a filter medium?

[mr.wilson]

Originally posted by beareef19
Mr Wilson
The info in those links would suggest that the shell is a good phosphate absorber, is this correct? If so why hasnt this been used is a filter medium?

Oyster shell is a common canister filter media for Koi. It removes much more than just phosphate through both chemical composition, and structure.

The problem is the bound phosphate must be exported, as it remains bio-available to nuisance algae. Algae will grow right on the site, and feed on the phosphate. Phosphate binders must be used to complete the process.

You could use it in a media bag in the sump and change it every month or so, according to load. It could also be used as "top dressing" for a remote DSB. You would have to skim the top layer off every month or so and replace it, or soak it in a weak acid solution to remove organophosphates.

This form of passive phosphate removal is what we had before aluminum, then iron binding agents. It isn't as efficient as these newer methods, but it's a cheap, renewable resource.

Randy Holmes Farley must have covered this topic in the chemistry forum, numerous times.

[Hobster]

Originally posted by mr.wilson
Randy Holmes Farley must have covered this topic in the chemistry forum, numerous times. [/B]

That is where I thought I read that crushed Oyster shells released a large amount of phosphate. I will check with Randy and ask him.

[Randy Holmes-Farley]

Here's a thread where we discussed this, and Habib reported results of phosphate leaching out of oyster shells:

http://reefcentral.com/forums/showth...hreadid=489121

Phosphate will be adsorbed into the shell structure in your tank, converting inorganic phosphate to organophosphates.

Phosphate does absorb onto calcium carbonate of all types, but that process does not convert it into organic compounds. Some organophosphate may also adsorb from the water onto calcium carbonate surfaces.

I discuss it here:

http://reefkeeping.com/issues/2006-09/rhf/index.php#10

[mr.wilson]

Thanks Randy. You're better than my Spell Checker.

[Randy Holmes-Farley]

Happy Reefing.

[beareef19]

If the oyster shell is a binder for phosphate and you use the shell in your wall or rock construction how will this effect the tank and its inhabitants , since you will not be able te export the bound phosphates from the rock or wall construction. Is this where the rowa phos, phos ban, phos guard come in to play to remove the organophosphates

[mr.wilson]

Originally posted by beareef19
If the oyster shell is a binder for phosphate and you use the shell in your wall or rock construction how will this effect the tank and its inhabitants , since you will not be able te export the bound phosphates from the rock or wall construction. Is this where the rowa phos, phos ban, phos guard come in to play to remove the organophosphates

You answered your own question. All calcareous surfaces absorb phosphate. It's just a matter of using an iron based absorption media, rather than biological processes to remove it. Some of that biological process being nuisance algae, and some of it healthy coral growth.

No, I'm not saying phosphates are beneficial, but they are inevitable ingredient in most of the things we add to our tanks.

The question at hand is "are you introducing too much phosphate with oyster shell"? Not all oyster shells are created equally. You need to test your batch to establish if it requires an acid bath to remove it. I haven't tested the oyster shell I use, but the tanks themselves haven't had elevated phosphates.

[Insane Reefer]

Originally posted by mr.wilson
...requires an acid bath to remove it...

Hi Mr. Wilson
Can you explain how this might be correctly and safely accomplished? I am going to be using oyster shell in my "commercial" rock, at least for certain lesser grades, and would like to know for certain that it isn't going to leech phosphates or anything else, except calcium compounds...

I will be working by the bag with this, could you please also include measurements for water and acid?

Thanks!

[piercho]

There are some very good descriptions of cement products and how to use them in here that have been most helpful for planning my next tank, which will have two 2" lines running down the back wall that need to be hidden. Thanks everyone, especially Mr Wilson, for the contributions.

I prefer PVC over ABS because it's certified for potable water.

I like ABS very much for pipe applications 1.5" and larger, and have used it in my tank. It was especially useful for an external 30 GPM air lift and RCSD system because of the sweep fittings. I don't know that it's reef-safe but IME it seemed reef-safe, and I think many of the black plastic thingies sold for aquarium use are molded ABS.

[mr.wilson]

Originally posted by Insane Reefer
Hi Mr. Wilson
Can you explain how this might be correctly and safely accomplished? I am going to be using oyster shell in my "commercial" rock, at least for certain lesser grades, and would like to know for certain that it isn't going to leech phosphates or anything else, except calcium compounds...

I will be working by the bag with this, could you please also include measurements for water and acid?

Thanks!

Test the oyster shell first, to see if it contains significant phosphate, before you worry too much about removing it. You should compare the results to that of "fresh" live rock and consider if it is worth the trouble. Changing the source of the shell is easier than treating it.

Phosphate is a surfactant, and thus easily removed with an acid spray. Large quantities however, should be soaked in a solution. Be careful when mixing acids and alkalines. Test your work before and after.

Spraying "old" live rock (from problematic algae tanks), with acid is a common practice. Use a 10% muriatic (hydrochloric) acid solution and follow safety guidelines including protective eye wear and apparel.

The (wet) curing process will also remove phosphate.

[beareef19]

Mr. Wilson,Have you ever used Perlite in any of your rock walls to reduce the weight? or is the composition of it detrimental to a marine aquarium and its inhabitants .....Reference...http://en.wikipedia.org/wiki/Perlite

[mr.wilson]

Originally posted by beareef19
Mr. Wilson,Have you ever used Perlite in any of your rock walls to reduce the weight? or is the composition of it detrimental to a marine aquarium and its inhabitants .....Reference...http://en.wikipedia.org/wiki/Perlite

I'm familiar with using it in planters, but the ingredients look a little scary for reef use (silicate and aluminum specifically). Weight isn't much of a concern when your throwing it in a 2000 pound tank.

[STEVEBEAM]

Hello Mr. Wilson,
First I would like to say that I enjoy reading your posts and respect your experience and knowledge in this field. With that said I have been following this thread and have a few questions.
I have a 210 gallon AGA aquarium and would like to apply shotcrete to the back and partial sides. You said that you applied the shotcrete directly to the glass. Is there any special surface prep that should be done prior to application directly to the glass? Should I leave a separation between the sides bottom and back of the tank for expansion and contraction?
What I am envisioning for my tank is to apply a scratch coat of shotcrete to the back and sides of my tank. Next I will cut dead coral rock with a wet saw and adhere these rocks along with coral rubble to the back and sides of the aquarium. I live in Miami Florida and coral rock is in great abundance. I will of course add plenty of live rock. Your thoughts? Thank You.

[mr.wilson]

Originally posted by STEVEBEAM
Hello Mr. Wilson,
First I would like to say that I enjoy reading your posts and respect your experience and knowledge in this field. With that said I have been following this thread and have a few questions.
I have a 210 gallon AGA aquarium and would like to apply shotcrete to the back and partial sides. You said that you applied the shotcrete directly to the glass. Is there any special surface prep that should be done prior to application directly to the glass? Should I leave a separation between the sides bottom and back of the tank for expansion and contraction?
What I am envisioning for my tank is to apply a scratch coat of shotcrete to the back and sides of my tank. Next I will cut dead coral rock with a wet saw and adhere these rocks along with coral rubble to the back and sides of the aquarium. I live in Miami Florida and coral rock is in great abundance. I will of course add plenty of live rock. Your thoughts? Thank You.

There are a number of cement bonding agents designed for wood, glass, steel, and adhering to old concrete. They are basically white glue. It looks like white glue, it smells like white glue, it has the consistency of white glue, and the instructions say that it can be used as....you guessed it...white glue.

The problem with white glue, is it's water soluble. It really aids in adhering the cement to glass, but it dissolves over the next month. Th cement still sticks, but you get stringy plastic-like pieces of glue all over the place. You could use water-proof yellow carpenters glue, but the cement wall is quite stable and will stay in place with gravity alone. Adhering to the wall isn't paramount in most cases.

If you use more cement mix and less aggregate (sand or shell), it will render a sticky mixture. It takes a bit of practice to work the cement into a malleable ball, that is dry enough to stick to the wall, yet wet enough to be workable. Quick setting cement is, as the name would suggest, quick setting. You will find that it will vary in setting time according to how well you mix it, and how much water you add. If you over-mix it, it seems to speed the chemical reaction, and you end up with unusable rocks.

My next project will use egg-crate panels and shelves as a base, and it will be built as a prefab insert (siliconed in place). Working vertically in the tank has its' challenges (gravity, access, and permanence). I will post pictures in the next couple of weeks.

I haven't used a separation point between panels, but it I can't see any negative aspects to doing so.

I would do a dry-stack with the rock. Hold it in place with plastic cable ties, where necessary. Then fill the gaps with cement & shell.

[GuySmilie]

My next project will use egg-crate panels and shelves as a base, and it will be built as a prefab insert (siliconed in place). Working vertically in the tank has its' challenges (gravity, access, and permanence). I will post pictures in the next couple of weeks.

I haven't used a separation point between panels, but it I can't see any negative aspects to doing so.

I would do a dry-stack with the rock. Hold it in place with plastic cable ties, where necessary. Then fill the gaps with cement & shell.

Very interesting info Mr. W. This really shortens the learning curve. I too have wanted to create the rock wall effect with cement but I've heard many say that applying cement directly to the glass will break the glass for certain. But I've never seen anyone justify why this would happen. Obviously, you have applied it directly to glass with no ill effects.

But Stevebeam brought up a good point and I did not see you address it. Should one leave separations (or seams) where the panels meet in the corners? IOW, would the cement expand upon curing and cause pressure on the intersecting panels and crack the glass? Or maybe the cement shrinks when it cures.

Another thought on making prefab panels; I would assume that it would be necessary to make the cement panels a little shorter than the actual distance of the glass expanse, in order to compensate for the silicone fillets in the corners. Is this correct?

Could you please elaborate a bit on these points?
Thanks!
Guy

[mr.wilson]

Originally posted by mr.wilson

I haven't used a separation point between panels, but it I can't see any negative aspects to doing so.

One problem with having a cement wall, is you may forget that it still has a delicate glass base. I don't know the effects of falling rocks, whether it dissipates the impact, or amplifies it.

I haven't noted any expansion or contraction. The polymer modified cement mix is designed to minimize shrinkage. I apply a thick (1"-3") coating, and haven't had a single crack. The cement does heat up, but only to about 100F. You can still hold it in your hand, and it only lasts a minute or two, not enough to crack the glass.

The bonding agent has instructions for affixing cement to glass, so I don't see how it would crack. I don't know how well it would work with thinner (1/4") glass. I did a 20 gallon tank 13 years ago with no damage to the glass, but the cement cracked like crazy. I used a hypertufa mix with portland and peat moss only. The cement dried too quickly.

It should be more convenient to build a prefab wall on a horizontal surface, and silicone it into the tank later. I'll let you know how it works out.

[STEVEBEAM]

Hello Everyone,

I am unable to find quantities of Quikwall in my area in small quantities. Lowes will special order but only by the pallet. LOL

Anyway Home depot carries this product: Sakrete Surface bonding cement.

http://bonsalamerican.com/sakretepro...16rdW6rO8po%3D

Thanks,
Steve

[Icefire]

I etched the rocks with vinegar and filled the tub with water.

Few hours later, PH 6.8, oily film on top, cloudy water, with a film covering the rock, easy removed if you poor water on it.

I used Bomix hydraulic cement. Any clue? Bacterial bloom?

I would doubt a bloom, it's not a tank...

[Icefire]

8.8+ PH now, guess I won't cut it.

[STEVEBEAM]

Mr. Wilson

Will this substitute for Quikwall??
Hello Everyone,

I am unable to find quantities of Quikwall in my area in small quantities. Lowes will special order but only by the pallet. LOL

Anyway Home depot carries this product: Sakrete Surface bonding cement.

A tech rep from sakrete said that this was their product that competes with quikwall.

http://bonsalamerican.com/sakretepr...=16rdW6rO8po%3D

Thanks,
Steve

[GuySmilie]

Bad link Steve!
Guy

[Insane Reefer]

Originally posted by Icefire
8.8+ PH now, guess I won't cut it.

If you buffer your system, and keep an eye on it, you could probably add a piece at a time over the next week