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Little Shop of Horrors - How EI frightened the gardener

LondonDragon said:
Could I use my tank water to water the house plants? Will they benefit from EI water? Just wondering

thatll be the best thing to do with it. I feed my greenhouse with my old tank water and everything thrives.

I syphon my tank water out the window straight into a large water butt outside, then I use that to feed/water everything in the garden. Running a 235ltre tank, it very rarely gets below half full.

its quite fun having everything on a cycle.. water change > greenhouse > then feed your cucumbers back to your snails! much fun.

We should be encouraging everyone to recycle their tank water in this way.. EI is incredibly heavy on water supplies. lets try to be as green as we can!
Matt Holbrook-Bull said:
We should be encouraging everyone to recycle their tank water in this way.. EI is incredibly heavy on water supplies. lets try to be as green as we can!
Thanks Matt I will sure be trying that from now on and see 😉
LondonDragon said:
Could I use my tank water to water the house plants? Will they benefit from EI water? Just wondering

After I did my last rescape while my other half was away for two weeks, I did the 50% water change at the end of the first week. I thought hmmmm what am I going to do with all this EI water :idea: Usually when she gets back half if not all the houseplants are dried up and not looking to good by the time she gets back. This time I used all the EI water on the houseplants. By the time she got back the plants were looking so good I think she thought I had been out and bought new ones. 😀 I'm still using this now and I don't feel half as guilty as before about the heavy water usage. 😀

Spread the word.


Hi Clive,

(pond question EI)

I have got a Moulded Damselfly 750 litre pond in my garden. It has got plants in, marginals, lillies and reeds and stuff but they never seem to flourish. The lillies never flower. I wondered if you could help me out with an EI dosing routine for 750 litres. I have bought the CHEMPAK PKN and Trace Elements from my local garden centre and they were dead cheap. The trace elements have got virtually the same if not exactly as the stuff that I got from AE. The only difference is that there seem to be some larger looking salt type crystals amongst the mixture that there is with the AE stuff. It cost £3.99 for a 500g box and the same for the 20x20x20 KPN.

Thanks as always,

Garden chemicals often have larger salt crystals in them due to the way they are stored and also because they are often a different grade. Sam chemical and same quality but not crushed as much.

They are either delivered to the fert manufacturers in bulk tippers (30 tonnes+) and dropped onto the floor in a bay ro they will be delivered in 1 tonne bulk bags.

Then they are stored in warehouses or sheds where the normal moisture in the air can often mean that a whole ton bag becomes one solid mass and the fert manufacturer has to pass them through a pulveriser to reduce their 'grain' again.

With there being no need for 'dust' for the purposes of their products the pulverisers are set to a faster level and therefore you get the little grains mixed in with 'dust'.

I would guess that most of AEs products are 'feed grade' products in that they are pulverised to a much finer grain. The quality and content of the product is the same but fed grade means that it is soluble.

I therefore get the pommel and granite out when I weigh out a new solution and even then some will stay at the bottom of the mix. I then shake the bottle before each dose so that any undissolved particles become suspended for a few seconds whil I draw the syringe.

Hi ceo,

I have a pond, but have never tried EI on it 😀 seems like a lot of ferts? but I guess it works as the added growth of the main plants, starve the algea (or shade it out etc).

Barley straw does work (green water only) as it breaks down, it releases ensimes, which prevent algea growth (green water only, IME).

However, there is another way (not saying better?) but an option, check out this link;

I have used this for past 3 years on a 1500 gall pond (gets 70 gal/night W/C from the exhaust of the Discus RO)
Apart from adding minimal ferts to the lillies (teaspoon of growmore/similar) it works well and is cost effective.

I also, drag out approx 1 wheel barrow/month (summer) of parrots-fern (or similar, don't know for sure!) which goes in the compost for the end of yaer mulch around the roses.

Cheers, Mick B
Hi Mick,
Algae cannot be starved out. It's more likely that the growing plants shade the water, remove NH4 from the water column and feed/oxygenate the water for the bacteria. Green water is less of a nuisance than blanket algae which is persistent and is a tough customer. EI on a pond is certainly over the top, I agree, but the main point is that the pond plants need to be fed the same as our submersed tank species. I reckon both barley straw and that viresco product are illusions. The exhaust from your Discus RO is loaded with nutrients and that's more likely to be the reason for your success.

It's just an exercise to show that you don't need to spend megabucks for "special pond products" or to even have much pond expertise to grow great plants. One can just pop down to Tesco or a garden shop and grab any NPK+trace product, chuck it in and Bob's your uncle. No barley, no special humic mumbo-jumbo, no voodoo, just a cup or two a week of Miracle Gro.😀

Hi ceo,

And I thought it was the Frogs!!! :lol: :lol: :lol: , but tend to agree, esp with mumbo-jumbo cost ££££££££'s

Same with Meds, for basic stuff, I use the pond stuff in the Discus tank, just have to check doseage etc, but in some cases, (skipping, the it's not as pure' comments') it can be 1000% cheaper!

Cheers, Mick B
I'm firmly on the barley straw side as it does work very well against green water in ponds. Not sure why or how though, but I've seen it many times. In aquariums people have had some success with adding willow branches to combat green water. I used to be quite against the idea of allelopathy in aquariums but must admit I'm starting to have second thoughts about it.

Yeah I've heard about the willow leaves as well. I'm not sure I would go so far as to say allelopathy but it could be that as the barley or willow decays some type of toxin is released which the green algae are particularly sensitive to. 😉

I had to chuck great quantities of barley that the gardener had placed in the pond. After a few weeks the green water went away so there must be some set of conditions, or maybe the toxins dilute after a while.

I guess the barley/willow thing is similar to the UV situation for green water.

Meaning that they remove the problem but not the cause. If you can prevent the cause then you prevent the cost of barley/willow/UV.

On Garden Direct 25kg bags are reasonably cheap.

Here's a barley straw study link I found while trolling through the Barr Report=> http://barleyworld.org/barleystraw/Barl ... 0Final.pdf

There doesn't seem to be anything definitive in the study, but it appears to be a combination of things starting from the release of phenolic compounds such as lignins as the barley decays and possibly the organic carbon sources that help jump start the microbial colonies at that time of year which then compete with the algae for N and P. This would probably be a similar situation with the willow. The document makes it clear that the barley can help prevent the development of some algal forms if place in the water early enough but has little effect after the onset of a bloom.

One little bit of info, which may be of interest;

If you crush a bit of willow (green not dormant) and soak in water, the water makes an excellent rooting-mixture for cuttings! for all you organic gardeners (Normal 'dry' gardening, not for Tanks), so hormones poss play a part?
I don't know if this is linked but the molecule Salicylic Acid is found in willow, which is what aspirin was derived from (acetyl salicylic acid).
Hi all,
Here is my pond (photograph taken on BH Monday), it has been run as nutrient poor as possible with rainwater and no added soil. The water went green initially after about a fortnight (for c. 10 days), but has been clear ever since. I get a a bloom of blanket weed (mainly Spirogyra )in the spring, but that declines as the leaves of the lilies etc. unfold, but there is always an algal "fuzz" on the stones.

I built it slightly raised, as the garden is on a slight slope, with the aim of not importing or exporting any soil from the site. It worked pretty well, with the soil going into a bed, and the rock from the hole (It was "Bath Stone" - Jurassic age "Superior Oolite" limestone, from only about 6" down) back into the pond to make marginal terraces. The hole is about 3000 litres, but there is only 2000 litres of water. The maximum depth is 60cm, with a deep central area and shallower marginal terraces. I built a shallow shelf at the sunniest point for the frogs to spawn in (the pond is on the N side of the house and only gets afternoon sun), its at the extreme right in the top corner in the top photo. I don't have any fish or a filter, but I added a "starter culture" of sediment and Hornwort (Ceratophyllum) from an established pond. Everything else has arrived on its own, with frogs, newts, Water boatman, Pond Skaters and Damselflies appearing almost as soon as the pond had water in (The exuviae on the Iris pseudacorus is a Southern Hawker Dragonfly.).

The planting is a mix of native and exotics (I've used as many native plants as I could find).

The water butt for topping up is just right of the door, and the bed with Candelabra Primulas (Primula japonica) is permanently wet, with the liner underneath. I've only topped up once since 2008.

I've got a lot of different plants, prominent ones in photo I haven't mentioned are Acorus gramineus "variegata", Mentha aquatica, Ranunculus lingua, Lychnis flos-cuculi, several sedges Carex spp. and Mimulus luteus. Best value buy was 12 assorted "old stock" pond plant pots for£10 from the local Ma Aquatics, and a bunch of water cress from the green grocers (flowering just towards the water, in front of the Primula.)

The remaining soil and rock went in the bed towards the house behind the Primulas, (with the flowering Aquilegia and a good yellow leaved grass - Millum effsusum "Bowles Yellow" in it). I bought concrete blocks for the retaining wall, sand & cement and the butyl liner (I did have one jointed together from off-cuts, but I couldn't stop it leaking, the underlay was carpet from the recycling centre and I got the slabs for the path from Freecycle), the total spend was under £400.

cheers Darrel
JamesC said:
I'm firmly on the barley straw side as it does work very well against green water in ponds. Not sure why or how though, but I've seen it many times. In aquariums people have had some success with adding willow branches to combat green water. I used to be quite against the idea of allelopathy in aquariums but must admit I'm starting to have second thoughts about it.


I'm not, we did a lot of studies on it here at the USDA lab at Davis.
Spencer at al found no significant effects due to the straw, who wants rotting straw in their pond that lowers DO levels?

Add more plants and then there's no algae, about 50% coverage is ideal and fairly easy to manage.
Been doing lake management for 5 years and every lake and pond is and has been algae free since I got involved.
Excess plants are removed and composted, if this trade off works, then it's a very viable method, for smaller ponds, this is the case, easy to pitch fork the Hyacinth etc and add to the garden or compost bin or sell on line etc.

Low maintenance, no algae, good cover for fish to avoid predators like birds, ducks, and herons etc.
Plenty of evidence shows this to be the case.

Allelopathy sounds nice, but as far evolution, plants compete much more amongst themselves than they do with algae, so why are there not more allelopathy occurring in between aquatic plants then? You cannot use the Evolution card and misapply it between plants and algae which are not in the same ecological niche, then not look at plant- plant allelopathy which are far more closely related niche wise.

I don't buy it.

Straw is cheap, it rots.
Many pond owners do like plants also, and would like some.
So plants are cheap and reproduce, can be composted and sold etc.
Work, well maybe the straw might work in some cases, maybe it's just correlation....... but one actually works well and in every case I've done, it's not the straw.
The water in the ponds is gin clear, this is true in Florida lakes as well. Remove the plants= algae/pea soup. Leave the plants, you can see 5-10 meters or more.

Tom Barr
dw1305's pond is testament to the principle of plants, not straw.
Nice clear water, full of nice pretty plants. No way algae can dominate that system, it's a little work, maybe some higher greens come in due to seasonal plant die back but that's temporary. Some pruning excess plants, selling them etc.
Plenty of emergent growth, nutrients are low.

So what would occur or would folks predict if he added say some KNO3/KH2PO4 to this system?
Algae? Or more weeds/aquatic plants?

What is dw1305's goal here also? More work and trimming of the plants? Probably not.
So adding ferts is only worthwhile if the plants are really strongly limited and growing poorly.
dw1305 cannot limit light too easily here, nor add CO2 etc, so nutrient management is about it.

The key is to pack the pond with plants and allow them to fill in and weedy out the algae while this process takes over.
Many add lots of plants in the spring, then weed good till the plants grow in, this is true for ponds as well as most terrestrial gardens in seasonal climates. End of March is algae time for us in CA in some of the ponds, so we get lots of floating plants in by mid March. Other ponds are more like this one above with marginals and emergent species and require little replanting year to year(best and I honestly like them more). More diversity, more critters, more things to look at and easier to care for once established.

You can add shade cloth during algae season, you can do manual removal, you can add various algae cleaners to the ponds, shrimps(imagine all the CRS you could raise?), various sucker fish can clean the stones. Another product is sodium percarbonate if you want to clean off the stones, very cheap and easy to use. Raises the Kh though. The powder drops on the rocks and dissolves H2O2 and kills the algae and sloughs off the rock. Works really well for this, will not harm plants though, I've tossed it on many species without any effect.

Also is a good laundry bleach alternative also, I use it for that instead of bleach along with borax.

I prefer biocontrol in ponds though, and plants are definitely biocontrol for algae. Fish/shrimp, snails can take care of the rest.

Tom Barr
Another trick if you own a pond+ aquarium, dump the old tank water into the pond.
This adds some nice softer water, with some nutrients and traces.
Tops off or water change(not needed typically if the % plant biomass is high).
Then take the water from the pond and use it for irrigation and landscape watering.
3 uses for the water this way.

Tom Barr