Changing Substrate

Not sure if this is the right board, but..

How easy / difficult is it to change substrate? When I first set up my tank years ago, I used gravel. Pretty much ever since I got the tank properly established I've kind of wished I'd used a smaller grained substrate, maybe even sand.

Last weekend I bought my first fish for years and I've suddenly thought that if I was to change the substrate, doing it before I restock fish would be a good idea.

Have I left it too late? I now have a total of 16 fish.

There's almost zero chance that I would be able to get my kuhli loaches out of the tank, so I'd need to be able to somehow do half the tank at a time.

And yes my tank is planted.

Would it be a reasonable suggestion to lower the level of the existing gravel and add sand on top? Would the sand just end up underneath the gravel?

I have sand as substrate in my tanks, and Matt is correct when he says that the waste sits on top of the sand. I do use a syphon to remove the waste, but I take the wide part of the end of the syphon, so it's just the tube in the water. Keep the end of the tube a couple of cm above the surface of the sand, and gentle swirl the tube to disturb the water near the substrate. This will move the waste up into the water, and you can then syphon it of with the tube. It can take a while to get used to doing this without sucking up too much sand, but if you are syphoning into a bucket then you can always out the sand back into the tank afterwards.
Whenever I've changed from gravel to sand I've always emptied the tank completely and started from scratch, starting with a growing substrate with a layer of sand on top. I'm lucky to have several spare tanks to keep the fish & equipment in whilst reworking a tank, so I can't offer any advice on changing substrate with fish still in the tank.
If you do decide to change to sand make sure it is smooth enough. I have bought aquarium sand previously which ended up being completely unsuitable as when I rubbed it between my fingers it felt quite sharp. This will not be any good for fish, such as your loaches, at the bottom of the tank because it will be too rough and cause damage.
 

I find sand easier than gravel. Cleaning it is so much easier as you can see where the muck is.

And a lot of plant people say plants grow better in sand with no special substrate underneath. They just need root tabs, preferably the kind that don't disintegrate (I've seen API root tabs named as the worst offender).


If you do get fish like apistos, sand is better for them, and even more so for rams. But I've never had kribs so I don't know about them. Apistos and rams feed like cories. Their natural way to feed is by taking a mouthful of sand, sifting it for bits of food then expelling the sand through their gills. They can't do this with gravel, but they still try. I had Bolivian rams on fine gravel and the female got a piece of gravel stuck in her throat. This is why I changed to sand.
And sand is the best substrate for kuhli loaches as they like to bury themselves.

I was quite inspired by @Aquarius Barbara's aquascape, which seems to be a combination of sand and gravel. It has got me thinking about how I could combine that in my tank.

I've been thinking about my general aquascaping, and how I can improve it. I was reading through my (really old) previous posts and found a conversation I had with Natalia about aquascaping. She suggested a 'path' towards the back to give the tank an impression of depth. I think that would work quite well in sand and would also be easier to get the gravel out and replace with sand.

The only downside is that the kuhlis like the plant cover and a sandy pathway would suggest that there are no / few plants in the sand!

I'll keep thinking...

Any ideas for an easy way to get the gravel out? A tea strainer? A ladel with holes would be perfect - do they exist? Ladels are usually for liquids!

I'll have to try the vacuum tube. If I'm careful, I should be able to stop it getting clogged. I might try reducing the level of the gravel first, slowly. I should be able to do that with my water changes and minimise disruption to the fish.

Thinking out loud - would garden hose be a bit wider than your siphon meaning the gravel would flow through easier?

If it's any help you could always have a look in your LFS either for a larger size syphon, or even at the hose they sell for attaching to large pumps.
When I was building the manifold for my river tank I bought hose by the meter from MA to attach it to the pump. They had several sizes available, so you should be able to find something useful.

I've had a quick look on their site and can't find the hose, but both my MA stores, and the independent LFS have a selection of sizes on large rolls, so I know that they stock it.

As for kids in the store, I know that most parents try very hard to keep their children behaving impeccably at the shops, because they care about the welfare of the fish, etc. However, don't let it ruin a visit to the shop for you.

One of the funniest things I have ever seen was at one of the quieter branches of MA, where I've got to know the staff quite well. During the school summer holidays I was chatting to one member of staff at the till, while the area manager was working in the office, and another member of staff was just heading to the office for a break. A fairly regular customer came in with his 4 kids (3 girls and 1 boy, all under 10), and the chap I was talking to went to the fish tanks with him. Within a matter of seconds it was like someone had released the demons of chaos, who scattered to the 4 winds to destroy the universe.
The dad continued his discussion with said member of staff as if nothing was happening. The kids ran riot around the store, picking up items, depositing them elsewhere, running up to the guys and asking questions, then dragging the member of staff around the store by the hand asking "what's this for?". They also asked him his name, then chanted it at the tops of their voices whilst running around. I was leaning against the counter and even I didn't get away without being asked several questions about items that the kids brought to me.
At one point I turned around to see that the boy had got a large net on a pole off the display, and had climbed on top of the pond fish enclosures, and was trying to net fish. I will admit that my response was to get my phone out because if this kid fell in the pictures were going to be hilarious, at which point he climbed down, put the net back and ran off to do something else.
After the longest 10-15 minutes in the life of the poor member of staff, the family left the shop.
The manager and other guy emerged from the office, and were asked why they didn't come out to help. They said that they thought he was doing fine, and it turns out that they were watching the whole thing in the office on the security cameras, and having quite a chuckle about it.

The lesson here is that even if your children cause a bit of mess there is a strong possibility that the staff are either just taking it in their stride as part of working at an aquatics store, or they have all gone to the office to have a good laugh as one member of staff tries to deal with the entire situation on their own. Either way, try not to let it interfere with your shopping, the staff are used to it. 

I was going to say that I'm not too worried about sorting gravel as it's fairly easy to get graded garden sieves.

Then it occurred to me that I might be able to get cheap metal kitchen sieve and use that as a scoop? Maybe a tea strainer?

I'm not sure my 4yo would be a reliable stone sorter. She also has an affinity for stones. I could easily find the large stones removed from the fish tank but distributed around my house!

I started removing the gravel with my siphon hose. Once I'd got the hang of it, especially avoiding larger stones that block the tube, it has turned out to be quite an efficient way of removing the gravel. I didn't need to get a short length of garden hose!

I got to the point where I was struggling to get more gravel out without catching plant leaves in the tube, so decided to remove plants, gravel and replant a third of the tank at a time.

So I've uprooted all my Vallis from my tank.  I decided the end result would look better if I trimmed off the runners, and replant the individual plants. I must have about 100 plants!  Think it'll take me longer to replant than I'd initially thought.

As well as the number of individual plants, that end of my tank looks extremely bare. It made me realise just how well planted my tank is.

Attached is a photo so far. I'll remove the gravel and replant after the kids have gone to bed tonight. Could be a late night!