Substrate on Substrate?

[connorlindeman]

I have some gravel as my substrate in my 20g and it's about 1 inch thick. I already bought a cory and I know that the gravel is not good for it.

Now to my question: Could I put sand on top of my gravel with the fish still in the tank? Would that work?

Also, is it really that bad for corys to be on gravel?

 

[Colin_T]

Sand will work its way through the gravel and it's pointless mixing them.

Sharp gravel can cut and scratch bottom dwelling fishes like loaches, eels and catfish. Smooth gravel isn't too bad. However, Corydoras like to sift sand when search for food so if you want to provide them with a natural environment, try to use sand.

You can add or remove gravel or sand while the fish are in the tank. However, lots of people prefer to remove the fish, drain the tank and remove the gravel. Then replace it with sand and set the tank back up.

Personally I just gravel clean the substrate one day. The next day I use a fish net to scoop the gravel out and put it in a bucket. Start at one end of the tank and then do the other end. Then push the remaining gravel to one side and remove that.

After the gravel has been removed, use a small bucket to add the cleaned sand to the tank. Add the sand at one end of the tank and gently spread it across to the middle. Then start adding sand to the other end.

Turn the filter off when adding sand to the tank so you don't suck sand into the filter. After the sand has been added and it has settled, turn the filter back on.

 

[connorlindeman]

Sand will work its way through the gravel and it's pointless mixing them.

Sharp gravel can cut and scratch bottom dwelling fishes like loaches, eels and catfish. Smooth gravel isn't too bad. However, Corydoras like to sift sand when search for food so if you want to provide them with a natural environment, try to use sand.

You can add or remove gravel or sand while the fish are in the tank. However, lots of people prefer to remove the fish, drain the tank and remove the gravel. Then replace it with sand and set the tank back up.

Personally I just gravel clean the substrate one day. The next day I use a fish net to scoop the gravel out and put it in a bucket. Start at one end of the tank and then do the other end. Then push the remaining gravel to one side and remove that.

After the gravel has been removed, use a small bucket to add the cleaned sand to the tank. Add the sand at one end of the tank and gently spread it across to the middle. Then start adding sand to the other end.

Turn the filter off when adding sand to the tank so you don't suck sand into the filter. After the sand has been added and it has settled, turn the filter back on.

that was very helpful. thanks!

 

[Oblio]

Thanks @Colin_T, I've got 125G (470 L) with about 1.5" (~4 cm) of gravel substrate and I really do not want to re-setup the tank. I'm thinking of play sand or BDBS. Am I correct in thinking that this could be done over several water changes, e.g. in thirds over 3 weeks?

 

[Colin_T]

I don't know what BDBS is?

You can change all the substrate on the same day or do it over several days. If you do it over several days, the sand and gravel will probably mix where it meets.

If you gravel clean the tank one day, then just remove all the gravel and replace it the following day. The gravel cleaning removes the gunk so the substrate is relatively clean. The following day you just scoop it out with a net and replace it with sand.

 

[Essjay]

BDBS = black diamond blasting sand

 

[connorlindeman]

I don't know what BDBS is?

You can change all the substrate on the same day or do it over several days. If you do it over several days, the sand and gravel will probably mix where it meets.

If you gravel clean the tank one day, then just remove all the gravel and replace it the following day. The gravel cleaning removes the gunk so the substrate is relatively clean. The following day you just scoop it out with a net and replace it with sand.

will this affect my beneficial bacteria at all?

 

[Byron]

Some issues here. First, do not use "blasting" sand in an aquarium if you intend substrate fish like cories or loaches. Blasting sand is by its very nature sharp, it is used to blast or break up concrete, etc. Quality play sand is fine if you want inexpensive safe sand, and as you are in the USA, look at Quikrete Play Sand available from Home Depot and Lowe's.. Or one of the aquarium sands, provided it is inert (some are calcareous, don't use those).

Second, change the entire substrate at the one go. This is far less stressful on fish, and it will achieve a better result. As Colin noted, the sand/gravel will mix if it is done piece-meal. A temporary tank to house the fish is best, then you can do the job properly. I've changed substrates several times and it is easy if done properly.

It has already been said, but yes, cories need fine smooth sand to be at their best.

The substrate is the filter bed of the aquarium, so replacing it will obviously remove bacteria of all sorts. But thy will reappear. Assuming there is a filter, keep it running (in the tank with the fish) and replace it when the substrate is finished. If you have live plants, especially floating plants, they will deal with the nitrifying issue anyway.

 

[connorlindeman]

Some issues here. First, do not use "blasting" sand in an aquarium if you intend substrate fish like cories or loaches. Blasting sand is by its very nature sharp, it is used to blast or break up concrete, etc. Quality play sand is fine if you want inexpensive safe sand, and as you are in the USA, look at Quikrete Play Sand available from Home Depot and Lowe's.. Or one of the aquarium sands, provided it is inert (some are calcareous, don't use those).

Second, change the entire substrate at the one go. This is far less stressful on fish, and it will achieve a better result. As Colin noted, the sand/gravel will mix if it is done piece-meal. A temporary tank to house the fish is best, then you can do the job properly. I've changed substrates several times and it is easy if done properly.

It has already been said, but yes, cories need fine smooth sand to be at their best.

The substrate is the filter bed of the aquarium, so replacing it will obviously remove bacteria of all sorts. But thy will reappear. Assuming there is a filter, keep it running (in the tank with the fish) and replace it when the substrate is finished. If you have live plants, especially floating plants, they will deal with the nitrifying issue anyway.

great advice!

 

[Oblio]

Some issues here. First, do not use "blasting" sand in an aquarium if you intend substrate fish like cories or loaches. Blasting sand is by its very nature sharp, it is used to blast or break up concrete, etc. Quality play sand is fine if you want inexpensive safe sand, and as you are in the USA, look at Quikrete Play Sand available from Home Depot and Lowe's.. Or one of the aquarium sands, provided it is inert (some are calcareous, don't use those).

I've read that blasting sand is not necessarily sharp and that it is it's hardness that makes it effective. It was also stated that sharp blasting sand is poor to use for blasting due to the sharp bits breaking off into fine particulates which are a silicosis danger. Note: I am not saying this is necessarily true, or not. I realize that the type of sand to use as a substrate is controversial.

 

[StandbySetting]

Blasting sand is definitely not good for bottom dwellers, it is coarse, sharp and angular. I work in an industry where this stuff is used all the time, it ruins everything it comes into contact with. Heck I can barely see the screen I'm typing on for scratches in my glasses caused by this stuff.

 

[itiwhetu]

Blasting sand is definitely not good for bottom dwellers, it is coarse, sharp and angular. I work in an industry where this stuff is used all the time, it ruins everything it comes into contact with. Heck I can barely see the screen I'm typing on for scratches in my glasses caused by this stuff.

This is where you need to be cautious using sand.

 

[DoubleDutch]

Blasting sand is definitely not good for bottom dwellers, it is coarse, sharp and angular. I work in an industry where this stuff is used all the time, it ruins everything it comes into contact with. Heck I can barely see the screen I'm typing on for scratches in my glasses caused by this stuff.

Don't get it in your lungs !

 

[AbbeysDad]

Just my $.02, but... If it was me, I'd remove the fish into a 5g bucket, then remove all the gravel, add 2-4" of sand, - either pool filter or play sand. After the 'dust' settled, I'd add the fish back in.

 

[Sgooosh]

i put lava rocks under my sand and it works but keep in mind i had a WHOLE LOT of sand