Category: Water additives

Ways to keep the water quality high

Aquasoil and water chemistry

Posted on by Andy Pierce
aquasoil

Aquasoil (there are various brands and types) is “an active bottom layer that lowers the pH value and slightly affects the water chemistry“.  One aspect is to slowly leach out fertiliser into the water column over time.  How about that ‘lowers the pH’ piece?  One way would be to have the aquasoil directly add acid to the water but that wouldn’t last very long.  Instead it is thought (although not published – trade secret) the aquasoil has an element of being an ion exchange matrix.  This means there are charged surfaces on the aquasoil that can be pre-loaded with either positively charged (cations) or negatively charged (anions) molecules.  These ions are slowly ‘exchangeable’ with ions of similar charge from the water column.  For pH lowering purposes, the aquasoil would need to come pre-charged with H+ ions, possibly in the form of ammonium (NH4+), which can be exchanged for calcium (Ca++) or magnesium (Mg++) from the water column.  The net effect would be to soften the water (removing Ca++/Mg++), add nitrogen based fertiliser (the ammonium) and to lower the pH of the water.  All three of these effects are thought to be beneficial in a planted aquarium.

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Low alkalinity Shrimphaus

Posted on by Andy Pierce

Despite all the advice to the contrary, I tried out some Caridina shrimp in the tapwater-based Shrimphaus.  This did not go well and after 3 weeks there was only one brave survivor left.  The usual way to keep soft water shrimp is to start with reverse-osmosis (RO) water which is selectively remineralised mostly to restore calcium and magnesium (general hardness – GH).  Alkalinity (KH) is usually kept pretty low.  The problem with this approach is that RO equipment can be expensive, takes up a good amount of space, and wastes a lot of water.  There is an interesting RO water supplier, Spotless Water, that has RO water vending stations distributed around England, but there aren’t any in the Cambridgeshire area.  Having RO water shipped in directly isn’t very practical.

What do to about that?

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Monolinuron does not control black beard algae

Posted on by Andy Pierce

After three weeks of treating the Shrimphaus with Tetra AlguMin in an attempt at chemical control of black beard algae, I can confidently report that monolinuron, the active ingredient in AlguMin, has absolutely no effect whatsoever on black beard algae (BBA, black brush algae).  The algae is as healthy and bushy as ever, does not scrub off even with vigorous rubbing, and may even have grown a little thicker.  I can’t really tell whether monolinuron was effective against green algae, as that wasn’t a major problem and so I wasn’t paying careful attention.  Certainly there was no visible green algae at the end of the treatment but there may not have been much in the first instance.

Monolinuron is safe for shrimp and snails

When used as directed at full strength, there were no adverse effects on either the zebra thorn snails, or on the cherry shrimp.  For a black beard algae reset, sterner measures are needed.

Chemical control of black beard algae

Posted on by Andy Pierce

Black beard algae (BBA, brush algae) used to be a bit of a nuisance in the Fireplace Aquarium, but since switching to a high phosphate, estimative index dosing regimen, BBA and really all forms of algae have been pretty much a non-issue.  Tanks need to sort their own equilibrium, and what works for the high-tech CO2-injected Fireplace Aquarium is not necessarily appropriate for the low tech Shrimphaus.  In general I prefer to ‘live and let live’ within reason for algae in an aquarium but in the Shrimphaus BBA has got to the point where it’s hurting the plants and not looking very pretty either.

What to do about it?

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Fighting algae with more phosphate

Posted on by Andy Pierce

The newly planted vallis seemed to be doing poorly with the leaves suffering structural damage and since vallis is thought to be sensitive to damage from liquid carbon I stopped the daily dosing of EasyCarbo.  Stopping the daily liquid carbon is something I had been thinking about doing anyway, on the grounds that with injected CO2 gas the “carbon” part definitely wasn’t needed and I was never really sure whether the daily low dose EasyCarbo (1 ml / 40 L) was suppressing green spot algae at all.  That said, I did notice what seems to be increased aggressiveness on the part of the algae in the weeks after stopping the daily liquid carbon.  What do to?  I would like to give the vallis a fighting chance to get established…

Low phosphate does not prevent algae

Despite a lot of misinformation in the popular literature, reducing phosphate is not a way to control algae, in fact, the low phosphate will adversely affect the plants in the aquarium reducing competition for algae.  In any event, with estimative index fertilisation, none of the major fertiliser components, including phosphate, are ever limiting and it’s well established that “excess” fertilizers do not promote algal growth in aquaria.

Can high phosphate prevent algae?

There are some tantalising anecdotal reports that high phosphate can prevent algae.  I have been dosing weekly phosphate to 3 ppm, but I’m going to give 7 ppm a try and see if that has any kind of noticeable effect.  Since it was time to mix up a fresh batch of macro fertilisers, it was very straightforward to boost the phosphates by adding just a little more KH2PO4.  My current macro mix is made up to a total of 500 ml and dosed 10 ml per day on Saturday, Monday, Wednesday into a 40 L water volume tank.

Macro MixTsp / 500 mlg / 500 mlWeekly ppm
KNO32.75 tsp16.5 g9.6 K, 15.2 NO3
KH2PO41 tsp6.6 g2.8 K, 6.9 PO4
MgSO4 ⋅ 7H2O6.5 tsp33.15 g4.9 Mg, 19.4 SO4
K2SO43.75 tsp19.125 g12.9 K, 15.8 SO4

Overall, this works out to 25.3 ppm K, 6.9 ppm PO4, 15.2 ppm NO3, 4.9 ppm Mg plus whatever is in the tap water used for water changes, which also probably contributes a few more ppm phosphate.

Happy with higher phosphate

It’s been more than a year now since I increased phosphate to 7 ppm per week and happily, in all that time I have not had to scrape down the walls of the Fireplace Aquarium to remove green spot algae.  I can’t say for sure it is the increased phosphate that has made the difference, but before increasing phosphate the tank needed an algae scrapedown on a roughly monthly basis.  Interestingly, I do get green spot algae growth in the water condensation on the lid of the tank, but not in the water column which supports the idea that something about the content of the water column is the difference maker there.

I have made 7 ppm weekly phosphate part of my permanent estimative index fertiliser strategy.