Mineral accretion

[KeysCoral]

Hi!
I am attempting an experiment to accrete minerals from seawater to grow a calcium layer on metal in a saltwater tank. I am running into some issues chemistry wise, because later on in my experiment I plan to introduce coral fragments, but I need to avoid things like chlorine buildup, iron, and ion loss in the water itself.
I'm wondering if anyone can guide me on a way to mimic what an Apex system might mitigate, but at a much simpler/cost effective level? I am not in a rush to introduce anything live to this tank, so as long as I can create consistent accretion I am happy to tweak the water quality again and again.
So in short, 1.) does anyone know how I can minimize the chlorine buildup that will occur around the anode in my system? 2.) due to metal needing to be the accretion substrate to complete the circuit, does anyone know how I can stop intrusion of iron into my system? 3.) Is there a manual (or digital at a low price point) way to dose for ion concentration?
I am able to "plumb" this system however I want, initially I was hoping for a static system to make my life easier, but if flow through is what will fix most of my issues (besides the chlorine) then maybe that's the way I need to go. I already have access to more advanced types of water quality monitoring like a ysi/sampling, which is why I am reluctant to go full scale with an Apex system.
Thanks in advance!

 

[Randy Holmes-Farley]

What do you mean by

I'm wondering if anyone can guide me on a way to mimic what an Apex system might mitigate, but at a much simpler/cost effective level?

What does an apex system mitigate in this context?

I presume you mean accretion driven by electrochemistry, which I think is going to have tox issues in a closed system that I do not see an easy way around, nor why it is desirable.

I guess I'm not understanding the whole idea. Solid precipitates do not themselves help corals.

It sounds like you are looking for a way to maintain alkalinity and calcium without dosing them? I do not think there's a way to do that.

There are lots of articles on seawater electrochemistry to make things like H2.

 

[KeysCoral]

What do you mean by

I'm wondering if anyone can guide me on a way to mimic what an Apex system might mitigate, but at a much simpler/cost effective level?

What does an apex system mitigate in this context?

I presume you mean accretion driven by electrochemistry, which I think is going to have tox issues in a closed system that I do not see an easy way around, nor why it is desirable.

I guess I'm not understanding the whole idea. Solid precipitates do not themselves help corals.

It sounds like you are looking for a way to maintain alkalinity and calcium without dosing them? I do not think there's a way to do that.

There are lots of articles on seawater electrochemistry to make things like H2.

Thanks for the reply!

This idea is still very much in infancy and I am open to input! I work at a land-based coral nursery and the goal is to use electrolysis to sequester calcium carbonate from our seawater tanks and let it accrete onto a substrate (for now I am planning to use rebar because it is cheap/accessible). By letting the calcium carbonate build up on the rebar, a layer will form, and then coral fragments will be adhered to that coated rebar with the hopes of increasing their growth rate.

I have access to a flow through system (I didn't realize that in my initial post), and so I should not have much issue with chlorine or deionized water, I am now just wondering if a system as thorough and constant as Apex is necessary to monitor my water quality for things like heavy metals, chlorine, or ion concentration, or if a simpler weekly water sampling kit would do the job?
I do also have access to further water analysis through an OA lab, I plan to monitor all the usual parameters using a ysi daily, and again coral will not be applied to the system for a while (I am thinking a month to allow for calcium buildup on the rebar).

I appreciate any thoughts you might have about issues I may run into, I am trying to troubleshoot as much as I can prior to fully setting up the system!

 

[Randy Holmes-Farley]

. By letting the calcium carbonate build up on the rebar, a layer will form, and then coral fragments will be adhered to that coated rebar with the hopes of increasing their growth rate.

Poking at that assumption, is the purpose of the calcium carbonate purely to allow them to adhere, or something else?

What would be increasing their growth rate? Nearby accreted calcium carbonate itself won't impact coral growth.

IMO, electrically stimulated coral growth comes from elevated pH and possibly alkalinity in the water. That is also why calcium carbonate accretes.

I know some of the Biorock authors like to claim it is more complicated and special, but I'm skeptical.

In any case, the goal of accreting the calcium carbonate is my main question. If you just want it there for adhesion, you could accrete the meta in the absence of corals, then add them.

 

[KeysCoral]

Poking at that assumption, is the purpose of the calcium carbonate purely to allow them to adhere, or something else?

What would be increasing their growth rate? Nearby accreted calcium carbonate itself won't impact coral growth.

IMO, electrically stimulated coral growth comes from elevated pH and possibly alkalinity in the water. That is also why calcium carbonate accretes.

I know some of the Biorock authors like to claim it is more complicated and special, but I'm skeptical.

In any case, the goal of accreting the calcium carbonate is my main question. If you just want it there for adhesion, you could accrete the meta in the absence of corals, then add them.

Hi Randy! Sorry I was away for a bit,

The goal is to sequester the calcium carb as well as other skeletal growth minerals to yes, increase the overall growth rate of the coral. Because of the anode/cathode/electrolysis the pH and alkalinity will be altered, so if you feel like that is the driving factor in increased growth then that still works for me!

Why are you not sold on Biorock? The initial company/methods aren't my favorite either, but since their patent ended other companies have popped up and I first hand saw the structures in Thailand, coral is growing on the electrified structures faster than the non-electrified.

I've been intrigued by mineral accretion and the relationship between quality of coral growth vs. growth rate for some time, hence why I am trying to figure out how to do it at a tank level which has never been done before from a data driven standpoint!

 

[Randy Holmes-Farley]

I think the accretion and the increased coral growth rate are are both caused by the same factors (e.g., pH and alkalinity) and that means that the accretion is not needed or useful to attain the increased coral growth. It is a byproduct. We see that clearly in reef tanks where corals grow faster at higher pH and higher alkalinity.

If testing it in a reef tank is just a model for what happens in the ocean to corals that attach, that's fine, but I worry that things like chlorine that normally dilute away will not be so diluted and one may get undesirable effects.

Second question is whether the mineral "surface" is especially well suited to collect natural marine organisms by natural attachment of juveniles. That may be true, but things also attach to metal, plastics, etc.. Reef tanks do not get a lot of natural growths so it's a difficult thing to assess in a reef tank. But in general, bare calcium carbonate surfaces do not seem better at attracting coralline algae, microalgae, diatoms, or dinoflagellates than do surfaces such as plastic and glass. Coralline algae, for example, is noted to attach to plastic surfaces before bare calcium carbonate rocks.

As to Biorock, I have no problem with the process overall, noting its severe limitation of being only a local solution to a small area, but they sometimes go off discussing ideas that the electricity itself is providing some benefit, which seems unjustified to me. This sort of statement seems to me like something you'd see on late night television for a secret fat burning pill:

"All other marine organisms examined also benefit. These amazing results happen because the Biorock™ process creates the ideal biophysical conditions that all forms of life use to make biochemical energy. This also has enormous implications for medicine and agriculture that we will develop."

Overall, the whole process obviously can work with or without electricity, but it seems to me more like creating underwater arboretums, rather than finding a way to preserve an entire forest.

 

[Randy Holmes-Farley]

I do not think an APEX has any capability of measuring metals or most other ions. If you want to measure metals, you'd likely want to go the ICP route.

Flow through would be good.