Reducing water changes: methods, benefits, challenges & discussion

[seabass]

We used to say that we need water changes to replenish consumed elements and export excess nutrients.  However, replenishing elements via water changes is inefficient (and dosing is still often required); plus, other means of nutrient removal are usually needed to supplement water changes.  We can replenish consumed elements by dosing supplements, and we can export nutrients through chemical media, refugiums, or even carbon dosing; but we can't remove detritus without changing some water.

 

While DOC can be dealt with by using activated carbon and/or a protein skimmer, the no change method doesn't address the organic build up on rock and especially in the substrate.  Also, the build up of things like sodium and chloride from additives can be brought back into check with water changes.  Because of this, I doubt that water changes will become extinct.  Although our reasons for doing so will likely change.

 

My water changes are an effort to deal with organics.  The result is usually a decent sized water change.  So I can't say that I follow the no change method.  I suppose with a bare bottom, high flow, and mechanical filters, the need to deal with organic removal would be limited.  It almost seems that this would be a prerequisite for this method.

[NanoRox]

40 minutes ago, seabass said:

While DOC can be dealt with by using activated carbon and/or a protein skimmer, the no change method doesn't address the organic build up on rock and especially in the substrate.  Also, the build up of things like sodium and chloride from additives can be brought back into check with water changes.  Because of this, I doubt that water changes will become extinct.  Although our reasons for doing so will likely change.

I agree.  I am not completely without changes myself but one way to address The physical build up of ditritus, etc is to mechanically disturb the substrate and rock surfaces, etc.  I am not alone in using a baster  to blast water into the substrate and rocks to dislodge ditritus and other build up to then be extracted via filtration.  I know it does not prevent all water changes but again through some modified husbandry routines, it does afford us the luxury of fewer water changes.   

[Subsea]

Without embracing nutrientrient recycling, zero water change is unrealistic.  I have gone more than a year with zero water change.  At that time I operated 6” Jaubert sand beds and used calcium reactors.  

 

@seabass

With respect to organic buildup in substrate, the right  detrivore crew will process that and make live food for the tank.  No need to take substrate out and wash it.  That is the food stock for detrivores to reproduce spores and larvae.

[seabass]

22 minutes ago, Subsea said:

With respect to organic buildup in substrate, the right  detrivore crew will process that and make live food for the tank.

I believe that you are correct.  I've read where working, true DSBs (6+ inches of sand) with lots of biodiversity, were taken apart after more than a decade, and the sand looked as clean as when it was put in.  But I wish I knew the secret; I never seem to be able to achieve the right balance, and end up doing most of the work myself.  I suspect it's from a lack of true detrivores and sand sifters.

 

I suspect flow and filtration might provide a big assist too.  Admittedly, my tanks traditionally suffer from a lack of flow.  It would be easy enough to remedy (as I have plenty of spare pumps).  Also, my 100 gallon tank just uses an oversized protein skimmer for filtration.  If I were to adjust my water change routine, I'd no doubt want to make several adjustments to my tank(s).

[Subsea]

PaulB rails against dsb.  He took his 45 year old set up down to move residence to Montauge Point at the end of Long Island.  It was set up as a reverse flow with 2” of dolomite, because they did not have aroggonite in those days.  I know success when I see it, so I set up my 120G new build with a reverse flow at just over 2” deep.  I see no reason for a focus on denitrification which is what dsb focus on.  I have meant Dr Ron twice.  While I agree with his focus on worms as beneficial detrivore inhabitants, I see  no reason to bring dsb into the conversation.  A fully aerobic 2 sand bed of the correct grain size will cycle  and feed your tank.

 

 

[Subsea]

While this is not a dsb thread, I would like to expound on one case study, my tank.  I had a Jaubert Plenum 6”+ deep for 25 years.  Because of Red Planaria infestation, in which I treated twice with Flatworm X, I added large Melanarious Wrasse which handled flatworms and every othe detrivore in sandbed.  After 24 years, my Jaubert Plenum with 6” sandbed failed.  Over a period of 4 weeks I siphoned out 4” of sandbed except one small area to allow wrasse to bury.

[seabass]

20 minutes ago, Subsea said:

I see  no reason to bring dsb into the conversation.

I'm not recommending a DSB, I'm just using it as an extreme example (primarily because many people consider it impossible to keep).  I had one fail myself (a DSB setup for seagrass).  However, I believe that it is possible given the right conditions and biodiversity.  It's definitely not for everybody, or for most, or for me.  I would typically warn people away from setting one up.  Instead, I recommend about an inch of sand, as this layer is typically very well oxygenated.

[Subsea]

I like 2”.  With a reverse flow, oxygenated water is pumped into void  then up thru the substrate which negates downward migration of detritus due to gravity.   I do not vacum this substrate, with one short exception due to cynobacteria.

[seabass]

9 minutes ago, Subsea said:

With a reverse flow, oxygenated water is pumped into void  then up thru the substrate which negates downward migration of detritus due to gravity.

I might have to explore that someday.