Sand over gravel

[Oli]

Thinking about changing back to a sand substrate. Since I’ve already spend so much on a good depth of gravel, and I have a number of plants rooted into the gravel, will it be okay to simply apply a top layer of sand straight on top. I would give the gravel a good vacuum before but I am worried about trapping ammonia and waste underneath.

If this is feasible, can someone recommend some good brands. (UK Only!)

 

[Byron]

No, putting sand on top of gravel willnot work, because the sand being smaller grain size will work its way down to the bottom with the gravel left on top. The only thing to do is change over the substrate completely, and at one go. The plants may be slightly set back, but I have moved plants around many times doing this or that, including changing all tank substrates to sand, and they quickly recover.

As for the ammonia and waste...obviously the waste is gone with the gravel. The substrate is the largest and most important bed for bacteria of many species, and this will be reduced but it quickly returns. You have plants so there should be no ammonia at all (that you can detect, or that will harm fish). Don't have the sand too deep; this partly depends upon the plants--for example, Echinodorus (swords) have extensive root systems and need space.

Argos Play Sand has been recommended by several UK members. Alternatively, you could get one of the aquarium river sands which are considerably more expensive but not problematic. Make sure it is inert (play sand is inert). Avoid pure black and pure white, both are problematic for fish.

 

[Oli]

Okay so it would be fine to remove all gravel at once without crashing the cycle?

 

[Byron]

Okay so it would be fine to remove all gravel at once without crashing the cycle?

Yes, because the plants handle the ammonia, cycling is in the background so to speak. Also, if you have a filter, and if there are fish in this tank now, you should move the fish to a "temporary" tank and you can move the filter over without cleaning it. Same when you return it to the new setup, though again with plants growing well you have no issues anyway. But over-caution is better than under.

 

[Oli]

I don’t have a secondary tank, will I be okay to just work around the fish?

 

[Byron]

I don’t have a secondary tank, will I be okay to just work around the fish?

This is not a good idea. Removing the substrate with fish present is highly stressful, and it risks encountering anaerobic areas than could poison the fish if disturbed. You can use a small tank, probably a 10g (don't know the size of the main tank), or some use one of those plastic containers. A cover is useful as fish may jump if startled.

 

[Oli]

I frequently disturb the substrate when vacuuming my gravel twice a week. How come this hasn’t released anything dangerous?

 

[Oli]

https/www.amazon.co.uk/My-Home-Essentials®-Flexible-Container/dp/B08VW7TH5Q/ref=mp_s_a_1_7?crid=22XR677EBEOPW&keywords=large+bucket&qid=1659302644&sprefix=large+buck%2Caps%2C82&sr=8-7

Would this work

 

[Byron]

I frequently disturb the substrate when vacuuming my gravel twice a week. How come this hasn’t released anything dangerous?

That may be very different. Normally, open areas of the substrate can be vacuumed, but not areas under chunks of wood, rock or decor. You do need some anaerobic areas, but they should never be disturbed.

 

[Lynnzer]

Well, thanks for this topic. I'm looking to do the same thing myself on a 60ltr tank that looks altogether too dark.
What I've thought of doing is to remove half the depth of dark substrate/gravel and replace it with light non toxic play sand BUT putting empty fertiliser bags between sand and existing substrate to prevent the sand from working its way to the bottom. I might even put a bit of fertiliser soil in the bags to aid plant growth too. I'm up to my neck with other things right now though so it'll be a couple of weeks before I make a start so in the meantime I'll keep a watch on this thread to see if any other ideas pop up

 

[TwoTankAmin]

A rubbermaid container will work fine. You can put your heater in it and your filter too.

Next, the mulm in the substrate is plant gold. Getting it into the sand is a good idea to the extent you can do it. If you do a deep vac before your remove the gravel save the nasty water you vac, out. Then put it back into the tank so it settles into the sand. That mulm will also contain some if the desired beneficial bacteria.

I do not normally vacuum the substrate in my planted tanks. I have a few that have never been vacuumed for over a decade.

However, mulm one the substrate when fish will contact it is not a good thing. Mulm in he substrate where it can be plant food is a good thing. Mulm will work its way into the substrate when there is some space for it to fall into. Fine grained sand is less condusive to housing mulm than small size gravel. Most unplanted tanks will need to some of the mulm removed regularl to prevent a build up.

Forget he fertilizer bag idea, change all of the substrate. You can add a bit of substrate fertilizer to the sand to give it a bit of a boost, but do not overdo this.

 

[kiko]

https/www.amazon.co.uk/My-Home-Essentials®-Flexible-Container/dp/B08VW7TH5Q/ref=mp_s_a_1_7?crid=22XR677EBEOPW&keywords=large+bucket&qid=1659302644&sprefix=large+buck%2Caps%2C82&sr=8-7

Would this work

any plastic container/bucket will work...just throw the fish in there...
don't wash the filter.....keep some of the water in a bucket like 50% of it...use the same bucket to keep the 50% water and fish xD
get the sand from the beach or a construction place...or if you're willing to fork out the high prices from a local fish store...
boil the sand and then filter it through a coffee/tea bag...
you might want root tabs or fertilizer as you killed everything in that sand...
dump all the sand in there put the root tabs and start the filter again with the old media inside...it'll help clear any residue/dust still in the sand
grab a net/mesh bag with some of the old gravel and put it in the tank for a couple weeks
and you should be set

 

[Colin_T]

I'm going against you all and say leave the fish in the tank. Just gravel clean the substrate the day or two before. Then scoop it out with a net. When all the gravel is out, add the sand.

Try to clean the sand the day before so you don't have to spend hours washing it before adding it to the tank.

If you remove the gravel from one side of the tank and then go to the opposite end and do the same, the fish can hang out at whichever side you aren't working in.

The fish will get stressed but they also get stressed when you chase and catch them, then move them into a holding tank for a few hours, then chase and catch them again to put back in the main tank. However, the choice is yours, but unless you're proficient at catching fish and have a spare container, I would just leave them in the tank and remove the gravel with a net.

Don't keep the gunky water from a gravel clean, that stuff is just nasty and contains way more harmful micro-organisms than good, and you can add a couple of aquarium plant fertiliser tablets to compensate for the lack of gunk in the new sand.

 

[Oli]

I'm going against you all and say leave the fish in the tank. Just gravel clean the substrate the day or two before. Then scoop it out with a net. When all the gravel is out, add the sand.

Try to clean the sand the day before so you don't have to spend hours washing it before adding it to the tank.

If you remove the gravel from one side of the tank and then go to the opposite end and do the same, the fish can hang out at whichever side you aren't working in.

The fish will get stressed but they also get stressed when you chase and catch them, then move them into a holding tank for a few hours, then chase and catch them again to put back in the main tank. However, the choice is yours, but unless you're proficient at catching fish and have a spare container, I would just leave them in the tank and remove the gravel with a net.

Don't keep the gunky water from a gravel clean, that stuff is just nasty and contains way more harmful micro-organisms than good, and you can add a couple of aquarium plant fertiliser tablets to compensate for the lack of gunk in the new sand.

This sounds like what I was planning. I also thought it would be very stressful catching all the fish, they don’t seem that bothered when vacuuming gravel and moving things around in the tank. This seems like a similar level of stress, I was only worried about when someone mentioned pockets of ammonia, however I do disturb the substrate twice a week anyway so seems like it should be okay

 

[GaryE]

I'm even worse as an influence. I did this in a couple of tanks recently, and just mixed in well rinsed sand with the existing gravel. I like the look.

The fish stayed in the tank, none the worse for the experience.