Are you concerned about DOC?

[p1u5h13r4m24]

The sheer number of options these days causes a lot of confusion. One thing that often gets lost in translation is that most reasonably good options will work for 12 months, the better ones 24 months, and only a select few will produce better than 50% success rates for 36+ months. The ones that didn’t work? Those people are no longer around to share their experience.

Part of why I like WC is it takes out the mad scientist element and replaces it with an option that just works. In most cases it works on things most reefers have never even considered.

• Foods: Nutrients (N/P) are obvious, DOC what you are asking about today. Consider the food, it's not just nitrogen and phosphorus, preservatives, elements, or other additives are accumulating.
• Element additives: Water changes help manage the inevitable trace element imbalances of our additives. None of them are perfectly matched to our tank’s uptake so over time some elements will rise/deplete. Coupled with a good additive system, WC/dilution will slow down and likely prevent dangerously high or low levels of most elements.
• Unintended contaminants: Anything aerosolized in the home or introduced via our hands. Some could be immediately toxic and others just build up over time and most are not going to show up on a ICP test kit.

I recently released a video that demonstrates what water changes are actually doing in the tank. 26:00 is the time stamp. It's a SR members video but here is link for a free month so you can see it without costing anything.

I absolutely agree. It’s kind of funny how we are beginning to back track to the original methods of reefing. Water changes and halides/t5s. Simple solutions rather than a salad of confusion. I always liked the waterchanges as a solution, but as I mentioned before lower nutrients from my all for reef dosing sort of limit me on the waterchanges. I have been cutting back the all for reef dosing and supplementing my all loss with kalk.

 

[bcarl77]

I follow the RM method and had stopped doing WCs for about a year. Test the tank very regularly, stay on top of ICP-MS and have always had low DOCs. The tank/coral health overall was performing better by doing regular AWC (2% a day) and I found I was adding less chemicals/products to address nutrient issues.

A WC is the best reset method for all things even the ones we can't/don't measure coming in through air pollution, RODI, aerosols, smoke from that steak you had for dinner last night, etc.

 

[LobsterOfJustice]

This is a deviation from your question and just my personal experience, but I really bought into the 'no water change' approach around 2017. I wanted to believe it was the evolution of reefing, but in the end, I spent more time chasing test kits and dosing bottles than it was worth. Any time I slipped up or got lazy with the mail in testing, there were immediate signs of trouble in the tank. I always felt like there were things the ICP wasn't testing for, like petroleum products, lotions, fragrances, aerosols, soap, and anything that could be on our hands or air.

The emergence of the DOC test, and your question, highlight the rabbit hole we tumble down in search of the perfect balance in a no-water-change environment. But ultimately, I stopped avoiding water changes and made them easier with AWC. The results were more stable, easier, and cheaper in the end. This is a journey that many of my peers have gone down as well. Excited about the opportunity but the ultimate lesson is "hey these WC are more valuable than I thought." Almost like a phase of reefing that we all go through :)

This is an example of an SPS tank I ran with zero filtration or gear, relying solely on AWC. Worrying about ICP/DOC/Unknowns just wasn’t a thing. Easiest tank of my life even though the coral density to water volume should have made it one of the most challenging. "

I'd encourage you to follow what interests you, implement and learn. Just don't get stock trying to jam the square peg in the round hole if it turns out to not be right for you.

Ryan, its so funny to read how you came full circle on this. I was one of those people watching you (and the hobby as a whole) putting so much effort into avoiding water changes thinking to myself "surely this cant be easier than just changing some water every 2 weeks?" :rolling-on-the-floor-laughing:. I'm with you in that the better solution is just to streamline and simplify the process of water changes to make it easier. I'm glad to see AWC available now but even before those were available, I always would plumb in my mixing tanks such that a water change mostly just involves turning a couple of valves.

ICP tests 20-30 elements, but not how those elements are arranged into a seemingly infinite number of molecules and compounds. Water changes are the great equalizer and will bring the bad stuff down and the good stuff up, FOR EVERYTHING. There could be 10, 100, 1000 deficiencies, toxins, or pollutants in your tank, and water changes help ALL OF THEM. This is one of the reasons why I have done regular partial water changes for 20 years, even if the water parameters test "perfect". You're only testing for a hand full of things but there are undoubtedly other compounds building up or depleting over time. And I think DOC is one of those things.

So to the topic at hand - yes I think DOC is a big player that has been overlooked. We do our best to emulate natures elemental/inorganic water chemistry, as well as light, flow, etc, but DOC is a huge difference between our home aquariums and nature. DOC is much higher in home recirculating systems and as it builds up over time, it is subjecting the corals to an un-natural environment.

 

[pooootiqe]

Just by the observation that most ornamental sponges die in an average reef aquarium seems to suggest that DOC alone isn’t enough to support their health. By the time enough phyto or bacterioplankton is dosed to keep them alive DOC is probably through the roof already…

Pineapple sponges though, those things grow like weed…

Like Randy said there seems to be a large discrepancy between what’s happening on the coral and what’s happening in our tank. Might be just fine though - some of the greatest achievements by mankind are culturing things in an environment far different from where they came from…

Btw, I think you’re focusing a bit more on the “waste and yellowing compound” and not “bacteria-degradable compounds” (like BOD5)?

 

[mboley]

I absolutely agree. It’s kind of funny how we are beginning to back track to the original methods of reefing. Water changes and halides/t5s. Simple solutions rather than a salad of confusion. I always liked the waterchanges as a solution, but as I mentioned before lower nutrients from my all for reef dosing sort of limit me on the waterchanges. I have been cutting back the all for reef dosing and supplementing my all loss with kalk.

How is All For Reef reducing nutrients? Isn't it just Alk, Calc, and trace elements?

 

[p1u5h13r4m24]

How is All For Reef reducing nutrients? Isn't it just Alk, Calc, and trace elements?

It's because the formate acts as a weak carbon source. In order for it to release its calcium and alkalinity it has to be processed by the bacteria in the tank.

 

[p1u5h13r4m24]

Many folks do such tests, as have I. But some methods, such as ozone, reduce yellowing without doing much for total doc.

​

​

Two digital photographs of a plastic bar taken through four feet of aquarium water. The bar on the left was taken before using ozone, and the bar on the right was taken after two weeks on ozone. The numbers were written onto the bar with marking pens. All camera settings were identical.​

Do you think that if someone wasn’t running ozone that a color test would be a good idea to determine estimated idea of DOC?

 

[Randy Holmes-Farley Verified Community Expert]

Do you think that if someone wasn’t running ozone that a color test would be a good idea to determine estimated idea of DOC?

I and others have tried to measure absorbance and not seen good results because the path length (amount of water the light is passing through) in a typical spectrometer or Hanna type device is too short. My photo was through 4 feet of water, massively increasing the absorbance over a typical 1 cm cuvette. Folks use buckets and such to do the same thing.

 

[Garf]

This is a deviation from your question and just my personal experience, but I really bought into the 'no water change' approach around 2017. I wanted to believe it was the evolution of reefing, but in the end, I spent more time chasing test kits and dosing bottles than it was worth. Any time I slipped up or got lazy with the mail in testing, there were immediate signs of trouble in the tank. I always felt like there were things the ICP wasn't testing for, like petroleum products, lotions, fragrances, aerosols, soap, and anything that could be on our hands or air.

The emergence of the DOC test, and your question, highlight the rabbit hole we tumble down in search of the perfect balance in a no-water-change environment. But ultimately, I stopped avoiding water changes and made them easier with AWC. The results were more stable, easier, and cheaper in the end. This is a journey that many of my peers have gone down as well. Excited about the opportunity but the ultimate lesson is "hey these WC are more valuable than I thought." Almost like a phase of reefing that we all go through :)

This is an example of an SPS tank I ran with zero filtration or gear, relying solely on AWC. Worrying about ICP/DOC/Unknowns just wasn’t a thing. Easiest tank of my life even though the coral density to water volume should have made it one of the most challenging. "

I'd encourage you to follow what interests you, implement and learn. Just don't get stock trying to jam the square peg in the round hole if it turns out to not be right for you.

I love waterchanges, but you gotta accept that 90% a month is hard to stomach for larger tanks. It appears 40% on smaller tanks is ok. How low can we go without the questionable ICP stuff?

 

[bcarl77]

Is ORP a good indicator of DOC levels? Would be interesting to see how those are correlated.

 

[Randy Holmes-Farley Verified Community Expert]

Is ORP a good indicator of DOC levels? Would be interesting to see how those are correlated.

Not really. I expect they are somewhat correlated, but ORP ultimately measures the relative balance of different chemical forms of the redox active trace elements, such as iron and manganese.

The fact that many people see an ORP drop after a water change, despite it lowering organics, is because of the trace element forms in the salt mix, such as the low ORP ferrous iron which is more soluble than the higher ORP form ferric iron.

 

[Ryan - Serious Reefs]

I love waterchanges, but you gotta accept that 90% a month is hard to stomach for larger tanks. It appears 40% on smaller tanks is ok. How low can we go without the questionable ICP stuff?

i agree that on big tanks filtration, testing and replenishment is a more attractive option.

What classifies a big tank? For me that’s any tank where 10% weekly, 20% biweekly or 35% a month is unmanageable.

Size of water change is probably the biggest factor I consider when contemplating “what is too big” for my own tanks.

 

[p1u5h13r4m24]

i agree that on big tanks filtration, testing and replenishment is a more attractive option.

What classifies a big tank? For me that’s any tank where 10% weekly, 20% biweekly or 35% a month is unmanageable.

Size of water change is probably the biggest factor I consider when contemplating “what is too big” for my own tanks.

I think in this scenario it would be best to do a mixture of all for reef and water changes. This way rather than a 10% wc a 5% may be more sufficient. I currently limited myself to a 120g system but I now am regretting going bigger. I don’t do as many water changes since I use both kalk and AFR. I’d got 3-4 months without wc. But I now have ramped those up to try and control DOC. Especially in the spring time with high pollen levels!

 

[Dan Reef]

Trying to control DOC means you are chasing a number: what number specifically?

Is there evidence of an appropriate level of DOC for a healthier tank?

Or it's "as low as possible"?

 

[p1u5h13r4m24]

I don’t think there is any evidence supporting that sponge claim in terms of usefully lowering doc in a typical reef tank.

I was just curious as to what about the current triton N-DOC test you don’t like in relation to testing for total DOC

 

[Randy Holmes-Farley Verified Community Expert]

I was just curious as to what about the current triton N-DOC test you don’t like in relation to testing for total DOC

Are you referring to a comment I made in this thread, or something else?

 

[p1u5h13r4m24]

This thread and I also seen you mention something in another thread.https://www.reef2reef.com/threads/n-doc-results.1062931/
I have been doing 10% weekly waterchanges and everything is great. I’m just trying to be proactive and not do too many water changes (assuming I’m maintaining nutrient N-10/P-.1) I’m under the assumption that too little DOC could also be a bad thing. I don’t think I need to worry because I feed heavy to maintain my nutrient levels but I’m just trying to understand better.

 

[bubbgee]

This just posted today off Reef Builders...

 

[p1u5h13r4m24]

This just posted today off Reef Builders...

I watched it already. It doesn’t explain my question to Randy about the accuracy of the triton N-DOC test which is my real concern. How low is too low and how can we accurately tell

 

[bubbgee]

I watched it already. It doesn’t explain my question to Randy about the accuracy of the triton N-DOC test which is my real concern. How low is too low and how can we accurately tell

I don't think we have enough data there yet. ICP has been around for almost two decades (triton introduced in 2008) but did not catch on until the past decade or so. Although I am worried about DOC in my tank (mostly because of coloration of SPS). Maybe as testing and new ideas come through the next two decades?