Brown Water?

6/20/99

QUESTION:

Dear Bates Family,
Thank you for providing this opportunity. We are at our wits' end! We installed a pond in spring of 1998 that is approximately 11' x 11' (plus a waterfall, which would render approximate dimensions 11' x 14'). We are using an Aquascapes kit with skimmer box and filter at one end and biofalls at the other. There is a flowering crab and a juneberry tree very near our pond. In fall 1998, when those trees starting losing their leaves, our pond water turned the color of strong tea. It remained that way all winter. In the spring thaw, it did clear out; that is, until the flowering crab starting to drop its blossoms. Then the same thing happened again. At this time, we attributed this to tannens in the leaves and flowers. After attending your spring maintenance pond seminar, we changed about 25% of the water and cleaned out the filter mats and as thoroughly as possible vacuumed out the pond with the pond vacuum we bought at Grassroots. We had been adding Aquascapes bacteria to the skimmer box at the recommended 1 teaspoon X 1000 gallons water twice a week (2 teaspoons). There was no change in the water color. We decided to "get radical" and changed all the pond water just before Memorial Day weekend, continuing to add bacteria at the same rate thereafter. The new water was perfectly clear, but within 5 days was back to the same "strong tea" color (and this time there were NO large quantities of leaves or flowers dropping). We were advised by a landscape designer friend that it might be brown algae and to begin adding 2 teaspoons bacteria DAILY for about two weeks. We have been doing this, but after the first week of this, there is still no discernible change in the water color. Also, the parrot's feather and pennywort we purchased at Grassroots the day of the pond seminar are alive, but not thriving. Our koi and goldfish seem to be doing fine.

Any thoughts or advice? Email us!
Thanks!

ANSWER:

Kevin,

This might not be as complicated an issue as it seems.

Brown water. 1 No tree leaves or other organic material in contact with the water? What about a cute piece of drift wood? If so try removing that.

2.Potting mix used with the plants. Is peat present? If so get that out as well.

3. Stone or gravel on the pond bottom? How much and how long has it been in the water? Lining the pond bottom with stone looks nice, but it does not allow for the needed oxygen to support the bacteria to digest (remove) the silt. After a few years the silt levels build up because the good bacteria can't live there to remove the silt for you. You may vacuum the pond until you can't vacuum anymore, but you will have a tough time removing the silt between the stone and the liner. That means you need to remove the stone to get the sludge out. Normally people only line their pond bottoms once with stone, after they shovel it out once they never want to do it again.

Test the pH. of the pond. If your pH is to high or to low the bacteria cannot work or will cease to exist. 6.8 to 8.0 is the range. That depends on the bacteria that you use. Test the pond in the morning at first light and again at 2 or 3 o'clock in the after noon. That will give you a best case and worse case to look at. Checking the buffers is standard while you are doing this.

Although I haven't seen this pond I am hanging a bet on peat and on the silt which can put the pH in a bad state of affairs as the buffers in the water drop.

I hope that this was helpful

Scott Bates

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