I'm returning to Dave's Garden after a long absence and seek advice from Dave's Garden fish keepers. We're hiring a landscape contractor to carry out our landscape designer's plan for our rear garden. Involved is an existing 300-gallon pond with our shubunkin goldfish which, after five years and subsequent generations, are pets to us. We have a 2,000 gallon capacity Bioforce with UV filter and have never lost any fish to disease or accident (its two ft. deep with straight sides and brick 'condos' for the fish so they are protected from predators). My biggest problem is ‘thinning the herd’ once in awhile and catching some fish to give away.
This is my question: We've decided to remove the flagstone, install a brick patio and our landscape designer is suggesting a brick edge around the pond to match the theme. We're using decomposed granite to fill in the patio and walkways, but she recommends using mortar with the bricks surrounding the pond to give stability to the edge. I'm concerned alkalinity will increase if water splashes on the bricks into the pond or if the bricks make contact with the pond when the water level is at it's highest. No mortar will be intentionally submerged. Should I be concerned that this amount of potential contact can change the alkalinity of a 300-gallon pond? The diameter of the pond is about six to seven feet. The container is a Rubbermaid agricultural tank with a medium gray edge which is flush to the ground level, so ideally we’d like to conceal the rim of the pond. If we cannot use brick, we’ll probably plant some type of grasses to conceal the edge but we'll be walking and stepping on them while working on the pond. Thank you for any information and suggestions you may have.
Question re brick and mortar construction & effect on PH
I did some research on this the other day, thinking I would like to do an above ground pond. I read the best way to neutralize with concrete is to let it dry for several days. The hardness with seal in most of the high ph. Then after you fill the pond keep fish out of it for a while and watch the PH. It will probably be a little high at first and then even out. Have also read that if it is just mortar that you are worrying about, it is such a small amount compared to a whole concrete pond that you shouldn't have to worry.
If you want to be safe they have a rubber paint on liner for cement. The stuff looks really cool and comes in several colors. Your pond sounds cool. Good luck!
Thank you, Evesta! The pond itself will have no mortar, just the bricks that will edge the pond at ground level. These fish are all pets and we'd hate for anything to happen to them so I guess I was just overly worried. Makes sense that splashing the brick edge with water isn't going to 'drip' enough alkaline into the pond to affect 300 gallons. The fish will remain in the pond during the landscape work so I’ll be sure my contractor knows to work carefully around them.
Thank you for your response – I appreciate the reassurance!