Ceramic frag plugs vs. Phosphate - initial test

[Who Dah?]

Phosphates inhibit coral growth and encourage algae growth. (Grrr... Phosphates...)

Do Fired Ceramic Frag Plugs leach Phosphate into the water? Another discussion on this board had me wondering this very question. Prior to someone saying that ceramic frag plugs leach phosphate into our tanks, it was my understanding that they did not. I thought that this was one of their major benefits. Hrm... It was suggested that there could be coral growth retardation near the surface of the plug due to this leaching. Hrm Hrm...

However, I wanted to know more. I use a lot of ceramic frag plugs and this knowledge could be very beneficial to me one way or the other. Anecdotal evidence is great! It's how we learn a lot about this hobby. But let's try to answer this for realsies.


So - I did a quick test. I'm not a scientist by any means, but I do happen to work at an analytical laboratory. (Kinda convenient for this sort of thing!)

Here's what I setup:

• Three 8 oz Styrofoam containers of DI water filled to near the top. The DI water is tested daily and is below 0.05ppm. (I can get the exact measurement in microsiemens if someone really wants to know.) The test took place for about a week.
  • Container 1: My blank. This had DI water in it the whole time, and nothing else.
  • Container 2: My Rinse Sample. This container contained DI water and 6 new ceramic frag plugs of various sizes in it. I rinsed out this container 4 or 5 times on each rinse day throughout the process. Sometimes the rinse days were 1 day apart, sometimes 2.
  • Container 3: My Non-Rinse Sample. This container contained DI water and 6 'identical' (same sizes) new ceramic frag plugs as in container 2. I did not rinse this sample out at all.

By now, I'm sure holes can be poked in my test. Styrofoam? Filled to "near the top"? Loose rinsing procedures? "About" a week? Let me say that the point of this test was just to see if a more detailed test was needed. If the results showed anything, we could do a more detailed test. If they didn't, we could prevent feeding the Time Goblin.


I also figured that in the real world, if there were any findings, that we would probably follow such procedures to 'cure' our plugs similar to how we cure aragocrete based plugs. I.e. try to rinse them every day, but miss days. (At least I know I'd miss days anyways.)


Now let's sound all scientificy! The test was run using EPA Method 300 on a Dionex IC instrument which has a PQL of 0.2 mg/L and a MDL of 0.07 mg/L for Phosphate-P.

The results after this roughly week-long process:

• Container 1: the blank
  • chloride: 1.29 mg/L
  • sulfate: 0.85 mg/L
  • phosphate-p: ND
  • fluoride: ND
• Container 2: the rinse sample
  • chloride: ND
  • sulfate: 2.77 mg/L
  • phosphate-p: 0.72 mg/L
  • fluoride: 0.11 mg/L
• Container 3: the non-rinse sample
  • chloride: 1.40 mg/L
  • sulfate: 41.36 mg/L
  • phosphate-p: 1.45 mg/L
  • fluoride: 2.70 mg/L

It appears to be that there could be something leaching here. Especially sulfate and phosphate-p. If these numbers were all ND, I'd probably stop here. But since there appears to be something happening here, looks like we need a more controlled experiment!

Does anyone know if such a thing has been done already so I'm not spinning my wheels here? If not, I'll continue with more precise methodology and documentation procedures (read: time consuming) from which we could draw statistical meaning.

Love to hear any feedback!

 

[Paul_N]

Nice work! It appears you are on to something here. My next question would be how much say 6 plugs would affect overall tank parameters of 100 gallons? If it is significant enough then is there a way they can cure the plugs like they do with the DIY rocks?

 

[BeakerBob]

Who Dah,
Good experiment! Just a couple of comments:

1) DI water is very powerful "solvent" in that it has had mineral ions (including sodium, calcium, iron, copper, chloride, and bromide) and other potential contaminants removed from it. Because of this, it will readily strip these components from anything it comes into contact with and absorb it. It is possible that the water is aggressively pulling the sulfate and phosphate ions out of the plugs and into the water to reach either saturation or equilibrium.

2) pH will play a great part in solubility of many compounds and their availability to complex with the hydrogen ion in water. To document what is happening in the saltwater tank, the water should be buffered and pH'd in the same manner as the normal tank water.

Having made these comments, I suspect that the use of DI water over tank water was to show a clean blank (control sample) and that tank water would never be ND (non-detect).

 

[inactive]

Thank you so much for this thread!

 

[wicked demon]

+1, hungry, acidic water can play a part, I would like to see the experiment duplicated with PH, TDS, and salinity controls.
Good work man!!!:bigsmile:

Who Dah,
Good experiment! Just a couple of comments:

1) DI water is very powerful "solvent" in that it has had mineral ions (including sodium, calcium, iron, copper, chloride, and bromide) and other potential contaminants removed from it. Because of this, it will readily strip these components from anything it comes into contact with and absorb it. It is possible that the water is aggressively pulling the sulfate and phosphate ions out of the plugs and into the water to reach either saturation or equilibrium.

2) pH will play a great part in solubility of many compounds and their availability to complex with the hydrogen ion in water. To document what is happening in the saltwater tank, the water should be buffered and pH'd in the same manner as the normal tank water.

Having made these comments, I suspect that the use of DI water over tank water was to show a clean blank (control sample) and that tank water would never be ND (non-detect).

 

[Who Dah?]

Paul PSU: we may be able to calculate/interpolate that once we have more data. The overall tank phosphate may or may not increase significantly to do anything, I'm not sure. Certainly dependent upon the ratio of X gallons to Y grams of ceramic to say the least.

Hi BeakerBob! I'm glad you were able to chime in. I was hoping you would! On Monday, I'll regroup w/ the chemists on running saltwater through that particular anions instrument. As I'm sure you can imagine, the high concentration of chloride in saltwater will certainly effect the peaks that instrument generates. I forget, how much Cl is in Saltwater? It's in the parts per thousand range, right? And our sulfate/phosphate-p hits are in ppm. I may be misspeaking here though as I'm not a chemist, feel free to correct me. This was the main reason I chose DI water. But having a 'perfectly clean' water source to start with did cross my mind as well. As you pointed out, at the very least, I could pH buffer the testing water.

Kraylen: you're welcome.

wicked demon: cool beans. I'll report back as mentioned above on Monday as to the viability of the same test w/ high concentrations of Sodium Chloride in the water.

 

[GrouperGenius]

Nice work Whodah. It's things like this that propel the hobby.


After all, in a way....we're all nerds. :nerd:

 

[Who Dah?]

Thx, GrouperGenius!

Today I found out that this particular method/instrument combination can't handle our saltwater as I had kinda suspected. The criteria for samples on this instrument requires a low TDS level so as to not clog it. We would have to dilute the sample significantly to accommodate the 'high' TDS level of our saltwater causing significantly less precision in the low-level results of the phosphate. The chemists are going to research to see if we can come up w/ a different combination of methods/instruments that we have in our arsenol. (She did comment that she thinks we can, but she needs to do some investigating.)

I do know of one alternative, but I'm not sure how much it would help us. Hey BeakerBob: what do you think about testing for straight P (as opposed to PO4) on an ICAP or ICPMS using EPA 6010 or EPA 6020? I know we can run saltwater on those instruments as we have several clients that give us saltwater samples to run. (Guess who gets to make the 'standards'? ) I'm just not sure if PO4 can be deduced from raw P?

 

[4Coral]

A lot would depend on the mix used to make the clay. We use slip to make our ceramic products. The slip we use is food grade and certified to be non-toxic. This is not the case with all clay mixes. I wonder what the fillers are in the mix that is not food grade?

 

[scrapz]

IME it seems as though fired ceramics have much more algae growth than any plugs I've used to date.

no relevance to the thread butmy favorite plug to this date is the agrocrete plug from boston aqua farms..

 

[Troylee]

bump for a great start!!!!
any conclusion on this????

 

[Limpits_Reef]

I have also noticed algae growth on my ceramic plugs, much more than I ever saw on agrocrete ones.

 

[Ian]

Right on J, I with I had the patience for this kind of stuff

I'd have made a thread on this DIY LED fixture I just finished

 

[stryker]

Excellent idea and test methods. The results are intriguing. I wonder if this has the same implications for the slew of fired ceramic products for the trade. I've seen large elaborate ceramic rockwork being sold more often now. The vendors claim that the firing process inhibits any leeching, but what else would they say.

 

[dfladermaus]

Total P would be fine Jeremy and it should not be affected by saltwater. A long time ago when I worked in a water quality lab we did Total P for all our saltwater and estuarine samples. The difference between total P and PO4 is usually not that great. You can blank out the difference in samples by running controls (Id say in triplicate to reduce error).

 

[m and m]

With such little chance 1. PPM wouldnt the adverage hobbiest who runs GFO not be bothered? Please correct me if im wrong but he added 6 plugs, in less then a gallon of water most of us have more then a 40g system so the change in a real system woul be less then what out electronics can detect. I feel as a hobbiest we wouldnt be adding enough plugs to be bothered by this. This does make me want to cure plugs before hand though just to play it safe. cure 100+ then throw them in the sump after werds.

 

[LegoZ81]

I would think as the coral encrusts the plug it slows the leaching of phosphate out to the tank water and would it would build up in the coral tissues/under the coral.

 

[gooch]

People need to realize that ceramics come from clay and clay is an organic matter. There are phosphates in everything. Do ceramic plugs and structures leach phosphates in significant numbers into our tanks? I do not believe so but it depends on who you ask. I wouldn't make the stuff if I thought it was detrimental to the livestock. And I have been doing this a long time.


As the above slip molder said they use food grade certified non toxic slip. Our clay is labeled the same way. Been using the same stuff for years and years. Will you get a phosphate reading in a cup of water. Yes. Drop a cube of fish food in that same water and do your test. Put a piece of liverock in the same eight ounces of water and test it. I'll betcha the readings will be higher. Phosphates are in everything and to a degree are used up by a lot of things. My guess is one feeding will probably put more phosphates into your water than 100 frag plugs or structures. I would also guess that the liverock you have in your tank also leaches more phosphate than anything. Phosphates have long been a problem even before anyone used ceramic materials for propagating. For every anecdotal response to ceramic inhibiting growth I can show you that leaching plastics and aragonite plugs do the same thing. One big boxed vendor let it slip to a distributor of mine that they had to cure the plugs they use for three months or more and they still have significant die off from it. They used concrete based plugs but have since switch to ceramic. My local store was sent some plastic magnetic frag racks from a distributor. He put it into the tank and it leached so bad that briopsis and hair algea went nuts. He got it uder control and now it only grows on this plastic rack. And it came from a well known vendor(not here). The briopsis came on an arogonite plug.

When it comes to judging growth your dealing with living animals and no matter how you try to judge things there are a lot of variables. We all know you can put two near identical corals in near identical situations and you will get different results. Everybody practices different husbandry and no two aquariums are the same.



Why do the ceramic plugs grow more algae? Well that also depends on the aquarium conditions. I can go take a 100 pics of ceramic plugs in action at my LFS. They keep the parameters in check. I don't see any bad algae growing on the plugs. They also get scores of corals on other surfaces and they have bad algaes on them from time to time. The ceramic is a clean surface and if bad algae is present it is a good chance the algae will settle on it. There is silica in a lot of clays and diatoms will feed on them. Just like they do on your aquarium glass.

The concrete based plugs are probably still leaching for months after you use them. Not only burning the corals but also preventing algae from forming. I guess I look at it like this. Algea will grow on everything in an aquarium. If it isn't growing on the plug doesn't that concern you at least a little?


We have been doing this for five years and we protect our material pretty well. And it is true not every ceramic is equal. Does this mean you can go get a full ceramic reef structure and put corals in it the next day? No. Ceramic is an alternative to liverock or concrete and plastic. It is natural and will take longer to cycle due to the fact you are starting with zero bacteria. People have been using ceramics in aquaria for probably as long as we have been keeping animals in glass boxes.

Everything has positives and negatives to it. You have to decide what works best for you. For me I went to ceramic because I felt with my experiences with it it was the best media for me. I only went into the business of selling them because others agreed. The positives far outweigh the negative.


I also must add that more than one hobbyist has put large pieces of our products into established home aquariums and had no spikes in phosphate or readings of phosphate from the tests that they take. So if they do leach either it is taken up rapidly or it is so insignificant that hobby test kits can not detect it leading myself and others to believe it is not a significant source of phosphates.

Also the Secore project has been using ceramic plugs for growing out acropora palmata in the caribean and closed systems. The results that we got back from that project were very promising. They would get up to 10 polyps settle on one plug. They purchased thousands of plugs from us and to the best of my knowledge are still using them.

 

[waxy]

I just thought the phosphates were inside the airbubbles that are trapped inside the ceramic.

When you soak the ceramic plugs in water, they create a ton of bubbles, I figured that's the Phos and Nitrates that are escaping.

 

[Who Dah?]

Wow - big 'ol bump! I nearly forgot about this. I haven't done any more w/ this scientifically, but I have been soaking my plugs in RO/DI and rotating the water every couple weeks prior to use for no other reason than it can't hurt and it prevents air bubbles from forming under the glue w/ new frags.

I can comment on this though:

They [Secore project] purchased thousands of plugs from us and to the best of my knowledge are still using them.

My personal comment: me too! Heck, I might be in the ten thousand range w/ gooch's plugs. Sound about right gooch?