Replace Substrate effect chemistry

[g6gang]

I am thinking of replacing my current <1 year old substrate (Bio-Activ Live Aragonite Samoa Pink) because I just don't like it - too many large pieces - much of it has hardened in places, battling cyano since the beginning, I don;t see any 'pink' like it was advertised etc). My question is, will this cause any chemistry imbalances during the process and how should I go about doing it? My tank is 80G mixed reef, and the sand bed is on the thin side of about 1"-1.5" deep. I am thinking of replacing it with another Aragonite based substrate and was thinking of just doing sections at a time (say 1/4 of the bed each week over the course of a month). Should I worry about reseeding Pods during/after this process as well?

 

[Randy Holmes-Farley Verified Community Expert]

You may notice a slight temporary decrease in alkalinity as the fresh sand may have some precipitation of calcium and magnesium carbonate on it.

A bigger concern is stirring up detritus and possibly hydrogen sulfide from under the sand. Do you have any black spots under the sand that you can see?

 

[g6gang]

No black spots that I can see. The sand is not very deep and is less then a year old. I read of people changing their sand on regular basis.

I also was going to siphon it out as part of a water change.

 

[Randy Holmes-Farley Verified Community Expert]

That's a reasonable plan.

 

[g6gang]

This article: Ron Shimek's Website...Deep Sand Beds also shed some light as to the effects of the substrate clumping. Seems like the clumping would also influence growth of Cyano in that same area of the clumping due to bacteria mismatch. So not only will I replace the DT sand, but I think I will also put a DSB in my refugium. I know there is controversy around DSB vs SSB so I will need to investigate further, but although my refugium is in the sump tank, I have it where it can be completely separated and turned off from the the flow cycle overflow goes to T controlled by valve - splits into Skimmer section and refugium that both flow to return pump section in middle. The fuge -> return section wall is higher then the other side so it can basically be a stand alone 10 gallon section. So not sure doing a 6" DSB in this 10 gallon section will have much of an impact on the 80G DT, but I think it is worth a try.

 

[beaslbob]

FWIW and IMHO an effective refugium with established fast growing macro algaes will trump what happens when you change the substrate.
my .02

 

[g6gang]

FWIW and IMHO an effective refugium with established fast growing macro algaes will trump what happens when you change the substrate.
my .02

I have not had much luck with Chaeto or Dragons Breath -

 

[Randy Holmes-Farley Verified Community Expert]

I'm not sure I accept Ron's assertions about how clumping is caused in all cases, but it is one possible theory and may be the explanation in some tanks.

 

[g6gang]

I'm not sure I accept Ron's assertions about how clumping is caused in all cases, but it is one possible theory and may be the explanation in some tanks.

He mentioned some way of seeing if it was that instead of calc related to see if the lump dissolves. I will try that..either way clumping cannot be good for the 'good' bacteria cycle ... especially with less then 2" of substrate.

 

[acidtablockshifty]

i have the exact same setup in my sump, except i have one emergency drain i let flow a bit, i was thinking about a deep sand bed when first started it but now that its running i dont think theres enough flow through it to acccomplish much in the fuge area. Its up to you but i like that i can just shop vac it out whenever i want, trying to syphion a sand bed with it low to the ground would be near impossible, and if you found it to be a detritus trap then while

 

[Randy Holmes-Farley Verified Community Expert]

He mentioned some way of seeing if it was that instead of calc related to see if the lump dissolves. I will try that..either way clumping cannot be good for the 'good' bacteria cycle ... especially with less then 2" of substrate.

Yes, I saw that. While I don't think it demonstrates exactly what he claimed, it will suggest whether organic material is a significant portion of what is binding the sand together.

 

[g6gang]

Yes, I saw that. While I don't think it demonstrates exactly what he claimed, it will suggest whether organic material is a significant portion of what is binding the sand together.

What mixture of bleach to water should I mix to get a "weak solution of household chlorine bleach"? 1:4?

"if a small sediment lump is placed in a weak solution of household chlorine bleach..."

 

[Randy Holmes-Farley Verified Community Expert]

That sounds fine for this purpose. Too strong will just be irritating to you, but won't change the conclusion that organics were involved in some fashion.

 

[beaslbob]

I have not had much luck with Chaeto or Dragons Breath -

Try again. :wink:
(I had problems with dragon's breath also.)
my .02

 

[asandbox]

Clean the sand before you put it in your tank. Get a shoe storage thing you put under your bed and put the sand in, fill with water, then do water changes, some people use a strainer to clean the sand, like that you get all the junk out

 

[s2minute]

So , i read somewhere about reclaiming old sand for reuse. I have a bucket of SD play sand that i suspect may be coated with PO4. How would i treat that to reuse?

 

[g6gang]

That sounds fine for this purpose. Too strong will just be irritating to you, but won't change the conclusion that organics were involved in some fashion.

How long do you think it would take to dissolve?. I have a 2" piece in a 50/50 bleach/water solution for a few hrs and so far nothing noticable. It was hard enough to maintain form but when pressed in my fingers it would fall apart.

 

[Randy Holmes-Farley Verified Community Expert]

I'd leave it a few days.

 

[g6gang]

I'd leave it a few days.

So it's been about 3 days and the clump has been unchanged. It did not lose any form or hardness. So from the article mentioned above, this would NOT be from organic bacteria and would most likely be caused by calcium carbonate or calcium phosphate precipitation? I know my calc was running >500 for a while, not sure if that had anything to do with it.

Either way I do not think the clumping was good for the areas and the little buggers that keep the sand clean hence helping my cyano problem (I do not have any cyano on the rocks)

 

[Randy Holmes-Farley Verified Community Expert]

So , i read somewhere about reclaiming old sand for reuse. I have a bucket of SD play sand that i suspect may be coated with PO4. How would i treat that to reuse?

Rock can be reclaimed by an acid wash, dissolving the outside layer. Sand may just be too difficult to remove enough but leave most of the sand.