The theory of water changes and their affect on water parameters

Uncle99

Crab Free Zone
Premium Member
So this is a genuine question. So we know that water replenishes elements in water. And we always reccomend to do water changes when something is out of whack. But my question is to what effect do the water changes help.

Say you have 100+nitrate and 3+ phosphate in an 10 gallon tank. In theory, doing a 50% water change should cut those numbers in half (provided you solve what’s causing those numbers). Is my thinking correct on this or would doing a 50% water change do only a 25% reduction in numbers? Thoughts?
Water changes add to the stability of our systems if done systemically and in the same proportion.
Your math is correct.
Not only do they contribute to the replenishment of those things taken from our water, but, to dilute those things we cannot easily test for (except ICP) and build up to potential toxic levels over months or years.
When reducing nitrates, it must be done a bit at a time if system has been maintaining this level for awhile.
Big changes equal big trouble.
 

reefing102

Who Am I Here?
Premium Member
I’d start daily water changes till those anemones look better

Make sure you have good gas exchange in the tank

Thats a lot of anemones for a 10 gal

Is this a temporary holding?

Definitely temporary. The tank is open on top with moderate surface agitation. No one around here really wants BTAs so they were super cheap and he was in a time crunch. I just don’t feel like going through nem vs coral wars in my 65 lol

Water changes add to the stability of our systems if done systemically and in the same proportion.
Your math is correct.
Not only do they contribute to the replenishment of those things taken from our water, but, to dilute those things we cannot easily test for (except ICP) and build up to potential toxic levels over months or years.
When reducing nitrates, it must be done a bit at a time if system has been maintaining this level for awhile.
Big changes equal big trouble.
I appreciate that! They are already perking up a lot more it seems from the water change. I also added carbon, a nitrate pad (one of those nitrate absorber things) and some phos-sorb. I’ll have her test them again in the morning to see where we are at.
 

Timfish

Timfish
Premium Member
I've always seen water changes as a good thing as there would be hydrophillic stuff that skimmers wouldn't remove and there would be stuff GAC wouldn't remove. Since I started keeping reefs in the late 80s I've learned we have to deal with particulate and dissolved orgainc and dissolved inorganic forms of carbon nitrogen and phosphorus. All of these forms influence, and are influenced by, microbial processes as well as corals, algae, sponges and other organisms. Research is showing corals, algae and sponges directly affect the microbial species in the water and corals are promoting microbial species beneficial to them while algae is promoting microbial species potentially pathogenic to corals. I now see water changes critical to the long term health and survival of reef ecosystems. Water changes not only remove excess nutrients, (carbon, nitrogen and phosphorus) but unlike skimmers and other mechanical and chemical forms of filtration they remove equally microbial populations in the water, both harmful to corals and beneficial to corals. As I see it water chagnes, along with removing nuisance types of algae, reduce equally the microbial levels and lets lets corals repopulate beneficial microbial populations.

Here's a data bomb:

Videos:

"Coral Reefs in the Microbial Seas" This video compliments Rohwer's book of the same title (Paper back is ~$20, Kindle is ~$10), both deal with the conflicting roles of the different types of DOC in reef ecosystems. While there is overlap bewteen his book and the video both have information not covered by the other and together give a broader view of the complex relationships found in reef ecosystems

Changing Seas - Mysterious Microbes

Nitrogen cycling in hte coral holobiont

BActeria and Sponges

Maintenance of Coral Reef Health (refferences at the end)

Optical Feedback Loop in Colorful Coral Bleaching
Optical Feedback Loop in Colorful Coral Bleaching / Curr. Biol., May 21, 2020 (Vol. 30, Issue 13)

Richard Ross What's up with phosphate"
What's up with phosphate? by Richard Ross | MACNA 2014

Phosphorus stuff:

An Experimental Mesocosm for Longterm Studies of Reef Corals

Phosphate Deficiency:
Nutrient enrichment can increase the susceptibility of reef corals to bleaching:

Ultrastructural Biomarkers in Symbiotic Algae Reflect the Availability of Dissolved Inorganic Nutrients and Particulate Food to the Reef Coral Holobiont:

Phosphate deficiency promotes coral bleaching and is reflected by the ultrastructure of symbiotic dinoflagellates

Effects of phosphate on growth and skeletal density in the scleractinian coral Acropora muricata: A controlled experimental approach

High phosphate uptake requirements of the scleractinian coral Stylophora pistillata

Phosphorus metabolism of reef organisms with algal symbionts


Sponge symbionts and the marine P cycle

Phosphorus sequestration in the form of polyphosphate by microbial symbionts in marine sponges

Fig 4 from "Phosphorus metabolism of reef organisms with algal symbionts"
DIP DOP POP.jpg

Nitrogen stuff:

Ammonium Uptake by Symbiotic and Aposymbiotic Reef Corals

Amino acids a source of nitrogen for corals

Urea a source of nitrogen for corals

Diazotrpophs a source of nitrogen for corals

Context Dependant Effects of Nutrient Loading on the Coral-Algal Mutualism

Fig. 3 from this last paper
Context‐dependent effects of nutrient loading on the coral–algal mutualism(1).png
 

Timfish

Timfish
Premium Member
Data bomb continued:

Carbon stuff:

Indirect effects of algae on coral: algae‐mediated, microbe‐induced coral mortality

Influence of coral and algal exudates on microbially mediated reef metabolism.
Coral DOC improves oxygen (autotrophy), algae DOC reduces oxygen (heterotrophy).

Role of elevated organic carbon levels and microbial activity in coral mortality

Effects of Coral Reef Benthic Primary Producers on Dissolved Organic Carbon and Microbial Activity
Algae releases significantly more DOC into the water than coral.

Pathologies and mortality rates caused by organic carbon and nutrient stressors in three Caribbean coral species.
Starch and sugars (doc) caused coral death but not high nitrates, phosphates or ammonium.

Visualization of oxygen distribution patterns caused by coral and algae

Biological oxygen demand optode analysis of coral reef-associated microbial communities exposed to algal exudates
Exposure to exudates derived from turf algae stimulated higher oxygen drawdown by the coral-associated bacteria.

Microbial ecology: Algae feed a shift on coral reefs

Coral and macroalgal exudates vary in neutral sugar composition and differentially enrich reef bacterioplankton lineages.

Sugar enrichment provides evidence for a role of nitrogen fixation in coral bleaching

Elevated ammonium delays the impairment of the coral-dinoflagellate symbiosis during labile carbon pollution
(here's an argument for maintaining heavy fish loads if you're carbon dosing)

Excess labile carbon promotes the expression of virulence factors in coral reef bacterioplankton

Unseen players shape benthic competition on coral reefs.

Allelochemicals Produced by Brown Macroalgae of the Lobophora Genus Are Active against Coral Larvae and Associated Bacteria, Supporting Pathogenic Shifts to Vibrio Dominance.

Macroalgae decrease growth and alter microbial community structure of the reef-building coral, Porites astreoides.

Macroalgal extracts induce bacterial assemblage shifts and sublethal tissue stress in Caribbean corals.

Biophysical and physiological processes causing oxygen loss from coral reefs.

Global microbialization of coral reefs
DDAM Proven

Coral Reef Microorganisms in a Changing Climate, Fig 3

Ecosystem Microbiology of Coral Reefs: Linking Genomic, Metabolomic, and Biogeochemical Dynamics from Animal Symbioses to Reefscape Processes


SPonge stuff:

Element cycling on tropical coral reefs.
This is Jasper de Geoij's ground breaking research on reef sponge finding some species process labile DOC 1000X faster than bacterioplankton. (The introduction is in Dutch but the content is in English.)

Sponge symbionts and the marine P cycle

Phosphorus sequestration in the form of polyphosphate by microbial symbionts in marine sponges

Differential recycling of coral and algal dissolved organic matter via the sponge loop.
Sponges treat DOC from algae differently than DOC from corals

A Vicious Circle? Altered Carbon and Nutrient Cycling May Explain the Low Resilience of Caribbean Coral Reefs

Surviving in a Marine Desert The Sponge Loop Retains Resources Within Coral Reefs
Dissolved organic carbon and nitrogen are quickly processed by sponges and released back into the reef food web in hours as carbon and nitrogen rich detritus.

Natural Diet of Coral-Excavating Sponges Consists Mainly of Dissolved Organic Carbon (DOC)

The Role of Marine Sponges in Carbon and Nitrogen Cycles of COral Reefs and Nearshore Environments.

And since we're discussing favorable and not so favorable bacteria here's a paper looking at how different corals and polyps are influencing the bacteria in the water column.
Aura-biomes are present in the water layer above coral reef benthic macro-organisms
 

Habib

CEO of Salifert
Premium Member
So this is a genuine question. So we know that water replenishes elements in water. And we always reccomend to do water changes when something is out of whack. But my question is to what effect do the water changes help.

Say you have 100+nitrate and 3+ phosphate in an 10 gallon tank. In theory, doing a 50% water change should cut those numbers in half (provided you solve what’s causing those numbers). Is my thinking correct on this or would doing a 50% water change do only a 25% reduction in numbers? Thoughts?

This will be true for nitrate but not neccessarily for phosphate.

If phosphate concentration is elevated, some of the phosphate will get adsorbed on live rock and sand. This will act as a reservoir. In such cases the impact of the water change on the phosphate IN the water can be much smaller than anticipated.

However, the phosphate reservoir will get depleted by increasing number of water changes, eventually resulting in normal effect of waterchanges on the phosphate concentration.
 

reefing102

Who Am I Here?
Premium Member
So quick update - nitrate is down to about 25 and phosphate is down to about .25/.5. Everything is looking a lot better, though still not fantastic but I realize that the sudden drop can affect them too.
 

kharmaguru

Premium Member
So quick update - nitrate is down to about 25 and phosphate is down to about .25/.5. Everything is looking a lot better, though still not fantastic but I realize that the sudden drop can affect them too.
So how big a water change did you ultimately do?
 

vlangel

Premium Member
What I learned about water changes is mostly practical nuts and bolts stuff. I maintenanced tanks for a fish store for 5 years. The stability I saw in those tanks because of consistent water changes spoke volumes to me and I became a believer.

I revamped my water change system to make them easy and my tank has benefited. I use tap water and rarely test parameters, ( only when something seems off) and even at that my tank does fairly well. I do not have a skimmer, or any reactors, only a refugium. Yes, it has the up and downs of all tanks that are up a number of years, but the downs are not deep valleys, just a few languishing coral here and there. I attribute that to small consistent water changes every week.

And although my preferred method is small consistent water changes, I had a gallon jar reef a few years ago and it flourished with weekly 100% water changes. It worked amazing. We would think so much disruption would be hard on the reef and yet the it flourished.
 

vlangel

Premium Member
That's so interesting. How long did you keep it running?
I can't remember for sure how long I kept it up but around 9 months. I was wrong about it being only 1 gallon, the jar was a 3 gallon jar. The beauty of it was the simplicity. It had a tiny rio pump and a par 38 led that just screwed into a regular light socket.
Here is a YouTube video of me feeding it frozen(which I think I did only once a week except a little bit of flake food for the shrimp, and then changing the water). I kept the jar because if I ever can not take care of a big reef I plan to at least have a jar reef or very small nano tank.
 

reefing102

Who Am I Here?
Premium Member
I can't remember for sure how long I kept it up but around 9 months. I was wrong about it being only 1 gallon, the jar was a 3 gallon jar. The beauty of it was the simplicity. It had a tiny rio pump and a par 38 led that just screwed into a regular light socket.
Here is a YouTube video of me feeding it frozen(which I think I did only once a week except a little bit of flake food for the shrimp, and then changing the water). I kept the jar because if I ever can not take care of a big reef I plan to at least have a jar reef or very small nano tank.
Not seeing a video
 
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