Thinking about redecorating: changing from sand to gravel

[Iris76]

Hi all, i could use your advise.

As much as i like the looks of my sandy substrate and the way my hillstreams are scratching it (i love it when they are flapping their fins over the sand and that it's blowing up next to them, like a speedboat that is cutting through the water ^^) , i'm still having trouble to keep it free from rotting. Luckily not overall because i wiggle it through weekly but around and in between the stacked pebbles, i noticed there are little rotting places. And since those are the places where my loaches hide and seek, i'm a bit worried and not satisfied with that. Therefor, i'm considering to change the sand to gravel. I think it'll be better for the hillstreams because their grazing grounds get bigger with the gravel but i am still doubting about the size. I don't want it to be too small, i want to be able to siphon the substrate without sucking it all up. I have a good siphon which i used in my former set-up but since i have sand, it's not in use. The gravel that i want to use is natural river gravel and it's tumbled.
It contains less chalk, it's mostly quartz like my sand so i don't think the hillstreams will have much trouble with adapting, since i expect the PH will not change dramatically. I plan to add a bacterial starter to support the balance in my filter and tank after the change.

There are 3 sizes and i doubt between medium and large.
I think small is out of the question because i think the siphon would sucks it all up while cleaning.

Small: 2-4 mm ( 0.08- 0.16 inch)
Medium: 3-5 mm ( 0.12 - 0.20 inch)
Large: 4-8 mm ( 0.16 - 0.31 inch)

I favour to mix 2 sizes, medium and large.
Or would the medium gravel fill up the places between the larger ones?
In that case, i would still have a substrate that suffocates itself.

If it's wiser to use one size i'd prefer the larger size, but i have Pseudogastromyzons.
Would that be too coarse for them to sweep aside if they plan to lay eggs?
Maybe the medium would be better, i really don't know what's wise.
I can imagine if i could use the largest size, i might be able to see some fry survive, due to the fact that eggs might sink into the gravel. Now eggs float all around the tank and/or end on the sand, which my dragon gobies and fanshrimp find no problem at all ...
Eversince i found out that my Ocellatus are in love, i'd figure that changing the substrate might contribute to save some fry. Nowadays, i haven't seen any fry survive.

After i have finally made my choise which size of gravel i'd use best, comes the question how to manage the changement. But, i'll get back on that later.

do's and dont's are very welcome.

[Diana]

You could set up a sand area right in front where it is easy to clean. Here is how I have set it up to keep the sand in one place, and not spread throughout the tank:

Use Expanding Foam Filler and rocks to make a solid retaining wall. There is a black one that is sold for pond use. It is fish safe. (The construction products are also fish safe, but not so subtle in color)
Make wahtever shape of an area you want.

I would go for the finer gravel. It will still vacuum like gravel (not much gets sucked out with the siphon).
If this is a not-planted tank you could remove most of the substrate, just use an inch or so.

What kind of sand do you have? The play sand sold around here is really bad for compacting. Must make nice sand castles! But it has so many fines and mixed sizes that it is bad for aquariums.
Pool filter sand has all the particles the same size, so does not compact. I have pool filter sand in several tanks. Works really well.

[NDininno]

I actually switched from gravel to sand and I used play sand (cleaned several times and sifted for sharper granules).

I used to aerate the sand using my siphon (homemade with pvc and a faucet nozzle thing with holes in it). I would just poke it into the sand occasionally in different spots. I got a few 'rotted' areas but honestly it never seemed to bother my fish or change the chem of the water at all. I stopped poking the sand like 9 months ago with no ill effect. In my experience I don't think it's that big of a deal.

[andyroo]

Define "rotting"?
Isn't this Methane pocketing in the sand? The bubbles just come up/out when a snail or loach digs through them.
I'd have thought this to not be a terrible thing as it's part of ye-'ol Nitrogen cycle...
Fish don't seem to mind, but if so I think I have a lot of work to do in my tank.....
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[andyroo]

I'm not big on my gravel as algae grows on it and the fish can't/don't eat it off the smaller stones. I think I may strain my gravel out and get more sand myself.
My Methane bubbles come about as the gravel tends to ride on top of the sand and keep it from jostling/moving/mixing.
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[Iris76]

Thnx for the helpfull reactions

@ Diana:
Your suggestion suits best to my likings.
The idea of combining sand and gravel is what i would like to see best.
In front of the glass is indeed where it's easy to clean because i have no trouble at all there to keep it clean.
And making a suitable wall to keep the sand in place is even great to do. I love making my own decorations, i did that with the waterfall too.
You asked which sand i was using and as a matter of fact, it is pool filter sand.
In the larger areas it's no trouble at all but between the pebbles it's clogging up and creating black areas.
Thank you for your good idea and i'll get back on this later, after the change. I'll keep you posted.


@ Andyroo:
It's especially about the algae why i think of changing from sand to gravel, it would widen their grazing grounds. And with rotting i indeed mean the methane that is blackening the sand. The methane is not bubbling up yet, i've never seen bubbles coming up from the sand.
It's more that i do not like the idea of anaerobe bacterias sickening my substrate, in a tank that is setup for hillstreams.
Hillstreams and anaerobe don't mix in my logica. Ok, i know that it's normal in a tank but i'd like to keep it in balance and it's obviously not the case right now. So, yes i do mind the methane and blackening spots in my substrate.
I see my Beaufortia's and Pseudogastromyzons scratch the substrate on a regular base and the idea that they are wriggling in a sick substrate, concerns me. Maybe i'm over-concerned but i do not like the sight of it and can not imagine it would not mind my fish.

@ NDininno:
Aerating the sand is a wonderful idea but the places where my sand is blackening, are exactly the areas i can not reach.
The places i can reach are free from methane, so i've got to try something else to keep it free from rotting.
I think changing my sand to gravel and keeping a 'beach' in front of the glass could do the trick.
To maintain 'the beach' i could use your trick, so i'll keep you posted on this. Thnx.


I'm about to change the substrate, still have some doubts about the size but to combine sand and gravel doesn't sound bad at all.
Now that i have an extra option to maintain the sand, i'm already a few steps further than yesterday.

[andyroo]

my black sand and my algae problems both stem from combining sand and gravel as the gravel "floats" atop the sand. The pea-gravel is stable enough to grow algae but too small for my algae-eaters (pleco and goby) to want to graze it, whereas the sand moves/rolls around a little so doesn't hold algae.
Try to keep the sand and the gravel separated.
If/when I ever do this again I'll be going with sand only.

[Diana]

I have more driftwood in my tanks, not so much rocks, except as retaining walls. Not usually sittong on top of sand (or gravel) but more often touching the glass at the bottom of the tank. I have the foam in a couple of tanks, and it works the best.

In tanks with just sand I do not cap it. There are a few odd pebbles in the sand, and with each gravel vac a new population of pebbles show up, and some sink.

[andyroo]

having said all that, my substrate is probably 30% snail-shells on the surface these days.... Definitely time for a straining.
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