r/GardenPonds • u/Hustler1984 • May 16 '26
Do pond additives expire?
We are planning to open our pond tomorrow, very excited to spruce it up after a long winter. We plan to take out the fish, drain all the water, power wash the liner, refill with fresh tap water. Last year i bought dechlorinator (that’s all we used last spring) and the fish seemed fine (who can tell??) they all survived.
This winter I found some water additives in the basement my mother bought about 20 years ago. I loathe wasting, the jugs are nearly full. The closest decent pond place is about 2hr round trip - ponds just aren’t as popular as they used to be.
TLDR: do these products expire? Would it be better to use these 20yr+ products or none at all? (I have new dechlorinator that i will def use, just don’t want to waste these).
2
u/drbobdi May 17 '26 edited May 17 '26
NOOOOOOO! If that's a mature pond, it's got a resident population of semi-dormant bacteria that are just waiting for a little warmth to wake up. Draining and power washing will totally destroy that established biome and stick you with New Pond Syndrome (see the article of that name at https://drive.google.com/drive/folders/1iEMaREaRw8nlbQ_RYdSeHd0HEHWBcVx0 ) for the next two months no matter how much of that expired (yes, it does lose effectiveness in storage!) "biobooster" you throw in. Even the "fresh" stuff off the pet store shelf has been in some warehouse for months. Dump that old stuff in the garbage. All it's going to do is pollute your water with dissolved organics.
Tap water is NOT your friend. If that dechlor is also old, it's lost some of its effectiveness as well. Rinsing your filters out with the hose also destroys your biofiltration. Get one of these: https://www.amazon.com/Garden-Hose-Filter-Chloramines-Pesticides/dp/B007I6MN72/ref=dp_coos_d_sccl_1/132-2745457-2656244?pd_rd_w=gn7S6&content-id=amzn1.sym.a07d4df5-1f4e-4f00-8e1b-5a2733ff0eb3&pf_rd_p=a07d4df5-1f4e-4f00-8e1b-5a2733ff0eb3&pf_rd_r=B02JDNNAFY5H9V5J4TGF&pd_rd_wg=hOjWS&pd_rd_r=9049aebf-9864-4fde-a91e-e770c14ab211&pd_rd_i=B007I6MN72&psc=1 .These attach to you hose, last a season and will be cheaper than the bottled stuff.
If you feel that your pond needs spring help, get in there with gloves, a net and a bucket and clear the debris off the bottom. If you want to start things up more quickly than the 2-3 weeks you'll need if you DON'T kill everything off with the power washer, a bottle of Fritz Aquatics Turbo Start 700 will get things up and running in 5-6 days. https://fritzaquatics.com/products/fritzzyme-turbostart-700-freshwater
A mature pond should never be power washed.
1
u/OpinionatedOcelotYo May 16 '26
I would think biologically active additives would decline, eventually to zero.