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/Aquatic Gardens, Design, Construction & Maintenance

Complete Cleaning, Acid and Bleach Washing


By Bob Fenner

Aquatic Gardens

Ponds, Streams, Waterfalls & Fountains:
Volume 1. Design & Construction
Volume 2. Maintenance, Stocking, Examples

V. 1 Print and eBook on Amazon
V. 2 Print and eBook on Amazon

by Robert (Bob) Fenner

"Yee-uck", "Be careful not to slip in the mucky-muck", goes a typical pond-cleaning conversation as the participants sink into the "primordial ooze". How many times have I been called on too aid a desperate fellow ponderer in finally getting 'round to scouring their ornamental "cesspool"? Way too many. If only they'd kept up with their regular vacuuming, netting and water change regimens!

From time to time all water effects require thorough cleanings. Elements of a total clean out involve dewatering, removing debris and livestock, if any, possibly chlorine bleaching, and or acid washing, refilling and treating chemically.

This Section details the procedures and precautions (it's slippery!) on how to clean your pond, fountain or reflecting pool.

These operations are nearly identical for those who acid wash plaster coated swimming pools and spas. Most all of the equipment and chemicals your system are available through your local pool supplier. An important note of caution here: be sure and use acid, or bleach contacting gear (for cleaning or for a pool/spa) only for these purposes. Can you imagine what will happen if chemical residue gets in with your livestock? Keep the biological and poison gear separated.

Once you've decided that your basin(s) need a thorough cleaning, there's too much gunk in the system, that an adequate cleaning cannot be effected by simple vacuuming and netting, the following steps are indicated.

DEWATERING- Love that term; dumping all the water out of the system can be a job in itself. In the best of circumstances, you will have a sloping bottom with a sump drain. In some cases you can siphon out most of the liquid with a garden or pool vacuum hose. The larger the hose diameter, and/or the greater the change in pond elevation, the better. If all else fails you may have to pump your system out.

Please be sure to check where all this water and glop you're removing is going to end up. Many municipalities require the use of a sewer, not the street storm drain system. If indeed you vent your discharge into a sewer clean-out, save yourself a bundle of headaches and screen out all solids that might clog your waste water system.

LIVESTOCK STORAGE- If your system involves fish and plants, you'll have to make provisions for safe storage. A clean trash can or kiddie wading pool will do for holding containers in many cases. If you use containers with a suspicious background or "plastic smell", guard against leakage and chemical contamination by using dark trash can bags or polyethylene liners (aka Visqueen).

Your holding containers should be fitted with adequate aeration/ circulation/ filtration. In the short term a small air pump and airstone will do. Cover your fish to protect them from jumping (they will). Refrain from feeding while in close quarters; your fish probably won't eat and it pollutes the water.

Very important note:

Many people lose their livestock in the process of complete clean outs. This is caused mainly by the change in the water chemistry and physical make up going from old to new water. The problem is that though it can't be "seen", the system's water changes with time and without frequent partial water changes, water quality may change so much that even though cleaning is a step in the right direction, it may be too much too soon.

One obvious way to reduce this source of trauma is 1) For several days prior to clean out, flush the system with new water 2) When transferring livestock, use a good portion, 50% or more, of the old water to house them. The most happy circumstance occurs in multiple basin systems where livestock can be kept in the same water.

REMOVING DEBRIS- A euphemism for trash. Once you've removed the water and livestock, it's time to figure out how to get rid of the muck on the bottom. If you're super lucky, you may be able to drain or siphon most all of this out. Otherwise you may have to pump, shovel, bucket, bail, net as much out as possible. The last of it may be removed with a wet/dry vacuum or net.

STOP!- I hasten to remind you, "cleanliness is not sterility"; you may be done at this point. "What, you ask?" "What about the stringy, slimy stuff stuck on the sides?" That "stuff" is part of the reason your pond stays so clear and clean; you want it, as long as it's not too unsightly. Don't be too quick to get rid of every last bit of "excess" greenery and muck; this is the matter that aids in cycling wastes.

If you have a "poisoned" system (one with nothing living in it like a fountain), have had an infectious disease in the system, or just want an entire "bright and sterile/clean" start-over, read on.

BLEACHING- Depending on the degree of cleanliness/sterility desired, bleaching and/or acid washing may be superfluous (read above again) so you may want to just refill, treat the water and return the livestock to the system. This is actually preferable in biological systems. In non-biological systems or where you want to check for cracks, prepare the surface for coating, sealing or patching, or sterilize the system for whatever reason, bleaching/acid washing is the way to go.

The choice of whether to bleach and or acid wash your system depends on how much stuff is growing in the system. If there's a lot of biological material, bleaching's the way to go. If chemical stains such as rust and scale are your only problem, then an acid washing's all you need.

Ordinary household chlorine bleach will do in a pinch, but swimming pool bleach is more concentrated and cost effective. This is best applied with a plastic watering can, by diluting about half to one third strength with water. The diluted bleach is sprinkled on the sides of the basin while they're still wet and allowed to soak for about 10 minutes.

I would suggest you wear your grubbies, rubber boots, and plastic gloves if you intend or need to get inside the system to scrub it out. Sometimes the bleach is best spread around with a swimming pool, acid washing or nylon brush. You'll find the dead and dying material has lost color and rinses off easily, though, in difficult cases you may have to rinse and repeat. After bleaching, keep rinsing and dewatering the system to remove as much bleach as possible.

ACID WASHING- This is typically done with muriatic, otherwise known as three molar hydrochloric (HCl) acid. Muriatic acid may be purchased from a pool service or masonry suppliers. As with chlorine bleach, though it is readily available through many sources, caution must be used when handling HCl. Precautions and emergency treatment are provided on the containers. Dilute as per chlorine with the adage "do as you oughta, add acid to water."

One precautionary note: NEVER mix acid and bleach together. If you need to chlorine bleach a system and acid wash to remove chemical stains, do the bleach job first, thoroughly rinse and dewater, then do the acid wash. The acid will foam and fume as it reacts with alkaline material so make sure you provide for plenty of ventilation. Apply, rinse, dewater, the same as for chlorine bleach.

Want to avoid the reaction smell? There is a simple, highly-effective technique for reducing fumes from the chlorine bleaching and acid washing. All that's involved is the addition of a few drops of liquid soap into the watering can.

REFILLING- For the most part no aquatic system should be left empty for any given period of time. An empty basin is too "attractive a nuisance" for children, and may crack from drying or outside pressure.

After cleaning and effecting any repairs, the system should be refilled as soon as possible. I would suggest overfilling and squirting off the top surface film to waste.

TREATING CHEMICALLY- What you may need to do to render your new water either 1) biologically safe for fish/plants or 2) chemically treated to restrict algae growth, varies as per your geographic water quality and weather conditions. When in doubt regarding water condition, check with your local aquarium shop or pool service company.

If you have fish and plants and you think you've treated the water sufficiently for re-introduction, test the water over night with an inexpensive fish or at least check for free chlorine with a cheap OTO or DPD pool chlorine test kit.

RETURNING LIVESTOCK- Put the fish and plants back as soon as you're sure it's safe. Take care to acclimate them slowly through mixing new water with old and/or floating in plastic bags to reduce thermal shock.

OVERVIEW- Non-biological systems frequently need dumping, chlorine bleaching/acid washing to keep them clean. Occasionally it is appropriate to do the same for biological systems in order to check for cracks, to do repairs or move large amounts of undesirable solids (beware the muck!). It is my hope that the information offered here will serve as a guide to make the job easier and safer.

Aquatic Gardens

Ponds, Streams, Waterfalls & Fountains:
Volume 1. Design & Construction
Volume 2. Maintenance, Stocking, Examples

V. 1 Print and eBook on Amazon
V. 2 Print and eBook on Amazon

by Robert (Bob) Fenner
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