"Would you be interested in growing your own bacteria to dose"
Yes.
How to grow your own denitrifying organic bacteria
I have developed a method using lawn fertiliser which is the method I am currently using and am about to try a second method which should be more controllable. This second method will require potassium phosphate and sodium nitrate.
I originally started my bacteria culture using tap water and a weak house plant fertiliser but the nitrate, phosphate and potassium (NPK) levels were too low and resulted in a very weak amount of bacteria. I have recently been using lawn fertiliser which is much more concentrated in NPK with great results. The NPK ratio of the lawn fertiliser is 38-5-5.
Materials:
2 Glass jars ca.200mL
Small plastic syringe
Lawn fertiliser with N-P-K ratio around; 38-5-5
Sugar
Synthetic seawater using RO water at ca.33ppt
5mL mature tank water
Glass 500mL jug
PO4 and NO3 test kits
Spoon scoops from supermarket (need ½ teaspoon scoop)
Method:
Add 300mL of sea water to one of the glass jars using the glass jug. Then add a level ½ teaspoon scoop of lawn fertiliser, put lid on the jar and swirl till dissolved (the water may have a green tinge), this will be our stock solution. Aerate for ca. 1 hour to oxidize any free iron which could cause problems later. Now fill the other jar with 250mL of sea water and add 50mL of the stock (seawater from the first jar). This new 50mg/L as NO3 saltwater media will be your bacteria media. Now take a sample and measure NO3. If you are unsure whether it is 50mg/L you can double check by taking 20mL of bacteria media and adding it to 80mL of seawater and testing it for NO3, this sample should contain 10mg/L NO3. If it doesn’t you can adjust the bacterial media by either diluting or adding more stock media till at around 50mg/L as NO3. Now add two table spoons of sugar to the bacteria media and swirl for about 30 seconds till some sugar is dissolved (there will be a sugar layer at the bottom; this is okay). Now add ca.5mL of mature tank water using a syringe to the bacteria media and close the lid securely. Swirl the jar daily and Monitor NO3 and PO4 content every 2 days until at 0mg/L this can take one to two weeks. It is very important that the jar is stored in the dark at room temperature to allow to ferment.
When at 0mg/L you have grown your first culture of anaerobic bacteria. Now you need to repeat the procedure, adding 50mL of the stock from before to 250mL of seawater in a jar but instead of adding a mass of sugar only add a teaspoon. Innoculate the new media by adding ca.5-10mL of the bacterial media from before and leave in the dark at room temperature again. Monitor NO3 and PO4 after 24 hours. If NO3 concentration and PO4 isn’t at 0mg/L add another teaspoon of sugar and leave for another 24 hours, repeat NO3 and PO4 test and one teaspoon of sugar addition every 24 hours until PO4 and NO3 are at 0mg/L. It should only take 2-4 days to reduce down to 0mg/L.
Once at 0mg/L this bacterial solution is ready to dose into your tank at a rate of around 3-6mL per 100 Gallons with carbon source daily until cyano is gone or just as a bacterial top up once per week. The bacteria is best to be stored in the fridge for up to 3 months, chilling the bacteria should put them into a dormant state but not kill them.
Phosphate in lawn fertiliser is in the form phosphorus pentoxide( P205) it cannot be measured by a phosphate kit (PO4) yet, when bacteria have broken down the majority of the nitrate they will break down phosphorus pentoxide to phosphate, this has been observed in my PO4 testing when the nitrate level in the bacterial media has been reduced to around 2.5mg/L - 5mg/L with a 1mg/L PO4 reading.
Organic bacteria will use oxygen whilst feeding on the sucrose until the oxygen level is completely depleted then use nitrate as a form of oxygen to respire while feeding on the sucrose. The first fermenter is used to get a good volume of bacteria and then the second fermenter is innoculated from this bacteria and carbon source slowly added to try to avoid too much excess sugar in the solution so that it can be stored.
This method has the added benefit of enhancing the organic bacteria already in your tank not adding foreign bacteria that might not survive in the conditions of your tank. It has been observed that bacteria can feed on other bacteria so even if there are dead bacteria they will be fed upon and aid your bacteria in your tank. Any excess dead bacteria not eaten by other bacteria will feed sponges and other filter feeders in the aquarium.
Phil aka philbo32 aka invert phil
