How much does 1tsp of malic acid equal in grams? I would imagine around 2-3g, I've never measured? I personally wouldn't take more than 1.5-2g by itself. Mixing it with apple sauce should make it more stomach friendly. I get unsweetened apple sauce as to not feed the bad guys more than necessary. Or take it in magnesium malate form.
As for colonics, I've had pretty good success with DIY suppositories and usually let Epsom Salt do its thing.