ok to use concrete blocks?

[Lillyspad]

I'm needing something to sit my pump on so that it isn't on the floor of my little pond.
Also need to sit potted plants at a certain level.
Is it ok to use concrete blocks. Will it hurt the fish.
Or what is suggested?
thanks in advance.

 

[RobAmy]

They can mess with the ph a bit. They can leach lime a bit. I would use milk crates or flues for inside a chimney would work also and act as a fish tunnel too

Use new flue also, they are 24" long but easy to cut with a masonry blade on a skill saw. You can different sizes.

 

[Sunshine]

I use milk crates to keep my pumps off the floor. The fish love swimming through the spaces. They would hold plants.

 

[shakaho]

Blocks that have been sitting outside for a long time are fine. You can get a concrete sealer and seal your blocks to prevent leaching if it worries you.

It's best to just do a test, since it probably depends on your water.. Put a block that you want to use in a tub of water. Test the pH before you you put it in, and every few days afterward. If the pH stays the same or does not change much, it's fine to use them.

 

[j.w]

I noticed some of the milk crates I see are reinforced w/ some metal. Would that still be ok or would you have to somehow get the metal off?
How about using the red bricks for houses............aren't they made of clay and safe?

 

[dieselplower]

I have had about 10 cinder blocks in my pond for 2 years. One death in the pond the entire time, sometime during this hard Winter.

 

[RobAmy]

I think there is confusion. They won't kill your fish directly. PH could be a issue that's all. Which could lead to problems. Depends on the size of the pond, etc. Just because it works for someone else does not mean it will be the best for your situation. I have seen block leech for years, also they will rot being fully submerged. It will take years
but they will. Like suggested maybe you could seal them but I think there are other materials that will work without all the hassle

 

[mrsclem]

I have used both concrete blocks and chimney flue liner. Love the flue liner but the edges can be very sharp so I pulled mine out.

 

[RobAmy]

I have used both concrete blocks and chimney flue liner. Love the flue liner but the edges can be very sharp so I pulled mine out.

Good point, I should of mentioned that, you can grind the edges smooth if you choose that route. I would even smooth the corners on the block also.

 

[morewater]

Use milk crates. They're light, you don't have to fight with them. No sharp edges. Full of holes. You can get them in black......and they're free (see codicil).

Codicil

I, for one, would never, ever, ever suggest any means (illegal, nefarious, skulking, pilfering, lifting, "borrowing", taking, scoffing....insert adjective) of obtaining said milk cartons that are not within the boundaries of ones conscience. As I've stated in the past, the humming of "Amazing Grace" during the actual act will serve as a salve to the wounded conscience. I myself have used this method on numerous occasions, and it has served me well. I highly recommend this mode of action.

 

[Mmathis]

What I would be most concerned about with concrete blocks has to do with

1. potential for damage to the liner [but that can be countered by placing a piece of space liner under the block, like a coaster]
2. potential for the fish to scrape themselves on the rough edges [though lots of people have blocks without this happening]

Plastic milk crates are pretty stable [IOW, not likely to tip over] so would think that could be a good base for your pump. Plus, the openings in the crates give fish nice places to hide.

 

[Mmathis]

Slightly off-topic, but..... I had no idea what a chimney flue liner was, so asked Mr. Google. Those are pretty cool! Turned sideways [and with all sharp edges smoothed off] those would make neat "hides." In fact, might even be something I could incorporate into my turtle habitat.

 

[j.w]

You could also put that plastic edging on those chimney flues....................you know the kind that just slips over and fits nice and tight. No sharp edges at all.

 

[Waterbug]

The idea that concrete blocks can change the pH in a pond is a very old myth. It was once an extremely popular myth. Less so these days. You can use the block without concern for pH, lime, etc. There is no reason to use old blocks, seal them, or anything else.

There is a chemical process concrete experiences that is kind of like rust, but with CO2 instead of O2, that seals concrete. This CO2 reaction happens with exposure to air or water. It takes an acid to remove that "rust".

So the exception would be if you were trying to force your pond to a very low pH for some reason, like 5, or 6 pH. At those levels the concrete might have a tiny effect, depending how much was used compared to water volume. But if you were keeping a pond at those pH levels you would already have a good understand of all this, so I assume this isn't the case.

 

[A. Dean Lynn]

The idea that concrete blocks can change the pH in a pond is a very old myth. It was once an extremely popular myth. Less so these days. You can use the block without concern for pH, lime, etc. There is no reason to use old blocks, seal them, or anything else.

There is a chemical process concrete experiences that is kind of like rust, but with CO2 instead of O2, that seals concrete. This CO2 reaction happens with exposure to air or water. It takes an acid to remove that "rust".

So the exception would be if you were trying to force your pond to a very low pH for some reason, like 5, or 6 pH. At those levels the concrete might have a tiny effect, depending how much was used compared to water volume. But if you were keeping a pond at those pH levels you would already have a good understand of all this, so I assume this isn't the case.

I truly enjoy reading about "myths" or "old wife's tales" as it adds to our hobbies. I am thinking about draining 1/2 of my pond and installing concrete steps. My pond was built in two stages so it is actually two ponds with duplicate return lines and suction lines. Thank you .